GPO, POST OFFICE and BT
MANUFACTURERS CODES


The British Post Office (BPO) purchased telephones and other apparatus from various manufacturers.  On a lot of equipment the manufacturer can be identified by the use of a manufacturers code.  Where a PO factory code is shown, that means that the equipment has been made or refurbished by one of the BPO factories.  Quite often these codes are on labels stuck over the top of the original manufacturer’s code.

It is clear that the original single-letter and later double-letter codes were allocated with fairly little regard to any logical meaning.  Once all codes were expanded to at least three letters greater care was taken to make meaningful combinations.  Existing two-letter codes were expanded by suffixing 'A' to the original code.  The list also includes some non-BPO codes commonly found on telephones (AP, YA and Z).

Thanks to many articles from the Telecom Heritage Group, especially the lists compiled by Graham Wooten, Andy Emerson, BT museum and John Ferris.
Code Manufacturer or Designer Notes Field of use
A Edison Swan Electric Co. Ltd Later 'BAA'
 
A9W Trench & Manhole Covers Ltd
 
Footway Boxes
AA Pinchin & Walton Ltd Later 'AAB'
 
AAA AEI Ltd - Ponders End, Enfield, Middx. Formerly Edison Swan Electric. See 'A' & 'BAA'
 
AAB Pinchin & Walton Ltd Prev. 'AA'
 
AAC Armstrong Addison & Co. - Sunderland
 

 
AAD Astralux Ltd - Colchester, Essex
 

 
AAE Coventry Controls Ltd - Coventry, Warwicks.
 

 
AAF London Transformer Products Ltd - London NW10
 

 
AAG Mullards Ltd - London SW18
 

 
AAL Cossar Radar & Electronics Ltd - Harlow, Middx.
 

 
AAR Plessey Co. Ltd - Havant, Hants.
 

 
AB A C Brown Ltd
 

 
ABC Scophony Baird Ltd - Wells, Somerset
 

 
AC Nalder Bros. & Thompson See 'N'
 
ACE C E Allen Ltd
 

 
ACL Advance Components Ltd - Walthamstow
 

 
ACW Automatic Coil Winder & Electrical Equipment Co. Ltd - London SW1 See 'AVO'
 
AD Spagnoletti Ltd - London See 'CN' Electrical Engineers
ADA Spagnoletti Ltd - London NW10 See 'CN' & 'AD' Electrical Engineers
ADL Elliott Addressing Machine Co. - London WC1
 

 
AE Medical Supply Association
 

 
AEG GEC Telecomms. Ltd - Glenrothes, Fifeshire, Scotland
 

 
AEK GEC-AEI Telecomms. - Kirkcaldy, Fife, Scotland
 
Exchange Equipment
AES Arthur East & Son
 

 
AEY AEI Ltd Telecomms. Group - Lower Sydenham, London SE26
 

 
AF Armstrong Bros. - Manchester
 

 
AG H W Bolt
 

 
AH J H Tucker & Co.
 

 
AHA Ernest F Moy Ltd - London NW1
 

 
AJ Consolidated Supply Co.
 

 
AJC Wheeler T (Scientific Instruments) Ltd - London EC1
 
Barometer 1A
AK Sterling Telephone & Electric Co. Ltd - Sterling Works, Dagenham, Essex Later 'AKA'
 
AKA Sterling Telephone & Electrical Co. - Dagenham, Essex Prev. 'AK'
 
AL W Robinson & Co. - Sheffield
 

 
AM Wrench Manufacturing Co.
 

 
AMW Amplivox Ltd - Wembley, Middx.
 

 
AN Ernest F Moy Ltd - London NW1
 

 
ANS Ansafone Ltd - Camberley, Surrey (Formed 1960) Now Alcatel Business Systems. See 'SPB'
 
AO Beck & Co. See 'AOA'
 
AOA R & J Beck Ltd See 'AO'
 
AP King & Scarborough
 

 
APB Aldridge Plastics Ltd - Birmingham
 
Head & Breast Sets
AQ Gambrell Brothers - Croydon, Surrey
 

 
AR Houghton Ltd
 

 
ASW Armstrong Stevens & Sons - Willenhall, Staffs.
 
Duct covers
AT McMillan & Co.
 

 
ATB Automatic Telephone & Electric (Bridgenorth) Ltd (Formed 1952)
 
VHF Radio Equipment
ATK Plessey Telecomms. - Kirby Trading Estate, Liverpool
 

 
ATL Austin Taylor Electrical Ltd - Bangor, N.Wales
 

 
ATW Automatic Telephone & Electric (Wigan) Ltd (From 1955) Orig. Pioneer Telephone Manufacturing Co. Ltd Mine telephones etc.
AU J Russel & Co. - Liverpool
 

 
AV Tylers Ltd Later 'AVB'
 
AVB Tylers Ltd Prev. 'AV'
 
AVO Avo Ltd - Dover, Kent
 

 
AW W F Dennis & Co.
 

 
AX H White & Co. - Yarmouth Later 'AXA'
 
AY R Lambert
 

 
AZ R & J Irving - Glasgow
 

 
B T Brittan Ltd Later 'BRI'
 
B2P Inventec Electronics (Malaysia)
 
Telephone (Duet)
BAA Edison Swan Electric Co. Ltd - Brimsdown, Ponders End, Middx. (later AEI Ltd) Prev. 'A'
 
BAB Edison Swan Electric Co. Ltd - Barton Hill Works, Bristol (later AEI Ltd)
 

 
BAF A F Bulgin & Co. Ltd - Barking, Essex
 

 
BB Brush Electrical Engineering Co.
 

 
BBK Bakelite Ltd - Birmingham
 

 
BBL Brittania Batteries Ltd
 

 
BC L Herve Ltd
 

 
BCC The Bristol Concrete Co. Ltd
 

 
BCL Bratt Colbran Ltd
 

 
BCN British Communication Corporation
 

 
BCR Belfast Cables Ltd - Newtown Abbey, N. Ireland
 

 
BD W T Henley's Telegraph Works Co. Ltd - North Woolwich, London E16 (Formed 1837) Later 'BDB'
 
BDB W T Henley's Telegraph Works Co. Ltd - North Woolwich, London E16 Prev. 'BD'. Later AEI
 
BE Callender's Cable & Construction Co. Ltd Later 'BEB'
 
BEA Barnet Ensign Ltd - London E17
 

 
BEB Callender's Cable & Construction Co. Ltd Prev. 'BE'
 
BEC Bradden Electrical
 

 
BEL The British Electric Lamps Ltd
 

 
BER British Electrical Resistance Co. - Enfield, Middx.
 

 
BET British Electric Transformer Co. Ltd
 

 
BF E Spencer & Co. - Manchester
 

 
BG Johnson & Phillips Ltd - Charlton, London SE7 (Est. 1875) Later 'BGA' Insulators
BGA Johnson & Phillips Ltd - Charlton, London SE7 (Est. 1875) Prev. 'BG' Insulators
BH Newton Chambers & Co. - Sheffield
 

 
BIW Berry's Electric Ltd - Birmingham
 

 
BJ Harcourts Ltd - Birmingham
 

 
BJB Bayliss, Jones & Bayliss Ltd - Wolverhampton
 

 
BK Magneta Time Co. Ltd (late Silent Electric Clock Co.) Later 'BKB'
 
BKA Bentley Engineering Co. - Leicester
 

 
BKB Magneta Time Co. - Leatherhead, Surrey Prev. 'BK'
 
BL A Bocchi
 

 
BLD Birkbys Plastics Ltd - Liversedge, W. Yorks. Part of Plessey Group Mouldings
BLG Blackman Leather Goods Co. - London SE1
 

 
BLW George Blagdon Ltd - Durham
 

 
BM H Wallis Later 'BMB'
 
BN Karabon Co. See 'EJ'
 
BNSF British NSF Co. Ltd
 

 
BO Standard Woodwork Co.
 

 
BPA Baker Platinum Ltd - High Holborn, London WC1 Part of Englehard Industries
 
BQ Stockall Marples & Co. Later 'BQB'
 
BQB Stockall Marples & Co. Prev. 'BQ'
 
BR Milner's Safe Co. Later 'BRB'
 
BRB Milner's Safe Co. Prev. 'BR'
 
BRD Bush Radio Ltd - London W4
 

 
BRI T Brittan Ltd Prev. 'B'
 
BS Everett, Edgecumbe & Co.
 

 
BSD Mullard Radio Valve Co. - Mitcham, Surrey See 'MUL' & 'MUW'
 
BT Prescot Clock & Mechanical Co. See 'BTB' Clocks
BTB Prescot Mechanism Co. Ltd - Preston, Lancs. See 'BT'
 
BTD AEI Ltd - Coventry
 

 
BTG Bell Telephone Manufacturing Co. - Ghent, Belgium
 

 
BTN AEI Ltd - Newcastle-under-Lyme, Staffs.
 

 
BTR Blick Time Recorders Ltd - London EC1
 

 
BTW AEI Ltd - Willesden, London NW
 

 
BU C H Glover & Co.
 

 
BUL Bullers Ltd - Stoke on Trent (1892-1959) See 'buljob' & 'bul' Insulators
BUR Burgess Products - Gateshead
 

 
BV Brown & Co. Later 'BVB'
 
BVB Brown & Co. Prev. 'BV'
 
BW A C Cossor Ltd - London N5
 
Valves
BX Williamson Clock Co. Ltd
 

 
C GEC Telephone Works Ltd (late Peel-Conner Co.) - Salford (1908-1921c) Moved to Coventry in 1921 (see 'GEC')
 
CA Blunden
 

 
CAB Correx Coms Equipment (1945) Ltd
 

 
CAC Clang Ltd - London NW2
 

 
CAD Cannon Elect (GB) Ltd - London EC1
 

 
CAO Cannon Elect (GB) Ltd - London N19
 

 
CB Chubb & Son's Lock & Safe Co. Ltd
 

 
CBD Salford Electrical Instruments - Birch Mill, Heywood, Lancs. (part of GEC) See 'SET' & 'SBM'
 
CC Carron Company Later 'CCA'
 
CCA Carron Company Prev. 'CC' Kiosk
CCB Creed & Co. Ltd - Brighton, Sussex
 

 
CCD Creed & Co. Ltd - Progress House, Croydon, Surrey See 'DV'
 
CD Malcolm & Co.
 

 
CE Boulton & Paul Ltd - Norwich
 

 
CEK Cray Electronics Ltd - Crayford, Kent
 

 
CEL Crypton Equipment Ltd - Bridgewater, Somerset.
 

 
CEM Carlisle Electrical Manufacturing Co.
 

 
CES Comark Electronics Co. Ltd - Littlehampton, Sussex.
 

 
CEW Circuit Electronics Ltd - Leamington Spa, Warwicks.
 

 
CF H W Sullivan - London SE15
 
Testing Apparatus
CFA H W Sullivan - Orpington, Kent Prev. 'CF' Testing Apparatus
CFR Craftsman Radio
 

 
CG Grimshaw, Baxter & Elliott
 

 
CH Alfred Graham & Co. - Halifax, Yorks. See 'CHA'
 
CHA AEI Ltd - Halifax, Yorks. See 'CH'
 
CJ Ingram Brothers - Glasgow
 

 
CK H White & Co. Ltd (Watchmakers) - London EC
 

 
CLB Ceag Ltd - London SW1
 
Lamps
CLS Concrete Ltd
 

 
CLV Colvern Ltd - Romford, Essex
 

 
CM Mitchell Ltd
 

 
CN Park Royal Engineering Co. Ltd Successors to Spagnoletti, see 'AD'.
 
CO D H Bonnella & Son Ltd - Hoddesdon, Herts. Later 'COA'
 
COA D H Bonnella & Son Ltd - Hoddesdon, Herts. Prev. 'CO'
 
CP Weston Electrical Instruments Ltd Later 'WCP'. See 'CPA'.
 
CPA Sangamo Weston Co. - Enfield, Middx See 'CP' & 'WCP' Voltmeter
CPL Crompton Parkinson Ltd - Chelmsford, Essex.
 

 
CPN British Cellophane Ltd - Bridgewater, Somerset
 

 
CR Crystalate Co. Later 'CRA'
 
CRA Crystalate Mouldings Ltd - Tonbridge, Kent Prev. 'CR' Mouldings
CRH Cossor Electronics Ltd - Highbury, London N5
 

 
CRJ Cossor Instruments Ltd - Highbury, London N5
 

 
CRR Cossor Electronics Ltd - Redhill, Surrey
 

 
CS E F Gurnett Later 'CSB'
 
CSA Clifford & Snell Ltd - Sutton, Surrey
 

 
CSB E F Gurnett Ltd - London NW1 Prev. 'CS'
 
CT Record Electrical Co. - Altrincham, Cheshire
 

 
CTC Chadburn Telegraphs Ltd - Liverpool
 

 
CTN Clear Tone Electronics - Newport, Mon.
 

 
CTP Creed & Co. Ltd - Pontypridd, Glamorgan
 

 
CTS Cooke Troughton & Simms Ltd - London SE7 Became Ophthalmic Opticians (SW1) Slide Rules
CU G L Beasley
 

 
CUL W B Cull & Sons, Birmingham
 

 
CUM Curtis Manufacturing Co. - Hammersmith, London W
 

 
CV T H Brooker & Co. Ltd Later 'CVB'
 
CVB T H Brooker & Co. Ltd Prev. 'CV'
 
CW Comyn Ching & Co. (London) Ltd - Sth. Ruislip, Middx.
 

 
cw Cox Walker Ltd
 

 
CWL Cambridge Works Ltd - Cambridge See 'PYE'
 
CWT The Caxton Wood Turnery Ltd
 

 
CX E Brook Ltd
 

 
CY Marconi Wireless Telegraph Co. Ltd - Chelmsford, Essex See 'CYA' Circuit Boards
CYA Marconi Co. Ltd - Chelmsford, Essex Prev. 'CY' Circuit Boards
CZ A P Buchanan
 

 
D India Rubber, Gutta Percha & Telegraph Works Co Ltd - Silvertown, London E (From 1864) Became Silvertown Rubber Co.
 
DA W Cowill & Sons
 

 
DAD A P Besson & Partner Ltd - Hove, W. Sussex See 'DAE'
 
DAE A P Besson - Hove, Sussex See 'DAD' Telephones
DAW Duct & Access Covers plc
 
Duct covers
DB John Gell Ltd Later 'DBA'
 
DBA John Gell Ltd Prev. 'DB'
 
DBK Bakelite Ltd - Durham
 

 
DC The Synchronome Co. See 'DCA'
 
DCA Synchronome Co. Ltd - Wembley, Middx. See 'DC'
 
DD William Duncan, Tucker, & Sons Ltd See 'DDA'
 
DDA Duncan Tucker (Tottenham) Ltd - London N15 See 'DD'
 
DE Muirhead & Co. - Beckenham, Kent Later 'DEA'
 
DEA Muirhead & Co. - Beckenham, Kent Prev. 'DE'
 
DEK Dover Engineering Co. - Dover, Kent.
 
Manhole Covers
DF British Telegraph Instrument Co.
 

 
DFM Denis Ferranti Meters Ltd - Bangor, N.Wales
 

 
DG Blake T C (Sykes Hydrometers) Ltd - London NW4
 

 
DH Willing & Co. - Brighton
 

 
DIR India Rubber, Gutta Percha & Telegraph Works Co Ltd - Silvertown, London E (From 1864) Became Silvertown Rubber Co.
 
DJ Telegraph Construction & Maintenance Co. (1864-1959) Amalgamation of Glass, Elliot & Co. & Gutta Percha Co. Taken over by BICC
 
DJA Telegraph Construction & Maintenance Co. (1864-1959) Amalgamation of Gutta Percha Co. & Glass, Elliot & Co.
 
DK Buck & Hickman Ltd - London E1
 
Tools
DKA Buck & Hickman Ltd - London E1 See 'DK' Tools
DL Drury Brothers - Liverpool
 

 
DM Vaughtons Ltd - BIrmingham
 

 
DMR Dynamo & Motor Repairs Ltd - Wembley, Middx.
 
Ringing Machines
DN H J Dawes Ltd
 

 
DNT E Dent & Co.
 

 
DO Grant, Cameron & Curle
 

 
DP Cheshire, Pooley & Co.
 

 
DPC Decca Radio & TV Ltd - Croydon, Surrey
 

 
DQ A W Gamage Ltd
 

 
DR Berry Skinner
 

 
DRD Dynamotor Repair Co. - London N1
 

 
DRL Dynatron Radio - Maidenhead, Berks.
 

 
DRP De La Rue Plastics Ltd - Regent Street, London W1 See 'LRA' Mouldings
DRT Decca Radio & Television - LONDON SW8
 

 
DS S G Jones
 

 
DT J Gerrard & Sons - Manchester
 

 
DTB Decca Radio & TV - Bridgnorth, Shropshire
 

 
DTW Duratube & Wire Co. - Feltham, Middx.
 

 
DU Cutlans Ltd
 

 
DUB Dubilier Condenser Co. (1921) Ltd See 'FE'
 
DV Creed & Co. - Telegraph House, Croydon, Surrey See 'CCD'
 
DVA Creed & Co. - Telegraph House, Croydon, Surrey Prev. 'DV'. See 'CCD'
 
DW Repetition Woodwork Co.
 

 
DXE Dexine Rubber & Ebonite Ltd - Rochdale, Lancs.
 

 
DY Staples & Co.
 

 
DYN Dynatron Electronics Ltd - Maidenhead
 

 
DZ Relay Automatic Telephone Co. Ltd - London (Formed 1915) Later 'DZA'
 
DZA Relay Automatic Telephone Co. Ltd - London (Formed 1915) Prev. 'DZ'
 
E Ericsson Telephones Ltd - Beeston, Notts. (1903- ) Later 'EET'
 
EA E Berry & Sons Later 'EAA'
 
EAA E Berry & Sons Prev. 'EA'
 
EB Francis & Son - London SE13
 

 
EBD Ever-Ready Co. (G.B.) Ltd - Bawley, Shropshire
 

 
EBL Edison Bell Ltd
 

 
EC C Lange
 

 
ECC Electric Construction Co. - London SW1
 

 
ECS English Clock & Systems Ltd - London N1
 

 
ED The Waltham Cross Joinery Co. Ltd
 

 
EDC Electro Dynamic Construction Co. Ltd - St. Mary Cray, Kent Now closed
 
EE Isenthal & Co. - London W3
 

 
EEB English Electric Co. - Bradford
 

 
EEC E Elliott Ltd - Walsall (formerly Birmingham)
 

 
EEL English Electric Co. - Liverpool
 

 
EES English Electric Co. - Stafford
 

 
EET Plessey - Beeston, Notts.(ex Ericsson Telephones Ltd) See 'E'
 
EEV English Electric Valve Co. - Chelmsford
 

 
EEX Plessey - Sunderland (ex Ericsson Telephones Ltd) See 'E' Exchange Relays
EEZ A C Egerton (Engineers) - Bromley, Kent
 

 
EF Albion Iron & Wire Works Co.
 

 
EFW F W Elliot Ltd
 

 
EG S E Norris & Co. - Dagenham, Essex
 

 
EH Cambridge Instrument Co. - London SW1 Later 'EHA'
 
EHA Cambridge Instrument Co. - London SW1 Prev. 'EH'
 
EIL Electronic Instruments Ltd - Richmond, Surrey
 

 
EJ C A Apperley 'See Karabon'
 
EJA C A Apperley 'See Karabon'
 
EK Clacton Joinery & Manufacturing Co.
 

 
EL Davis & Timmins
 

 
ELE Engineering & Light Equipment Co. Ltd
 

 
EM B.K.B. Electric Motors Ltd - London WC1
 

 
EME EMI Electronics Ltd - Feltham, Middx.
 

 
EMI EMI (Valve Divn.) - Ruislip, Middx.
 

 
EMM Electro Mechanical Mfg Co. - London WC2
 

 
EN British Time Recorder Ltd - London EC1 Later 'ENA'
 
ENA British Time Recorder Ltd - London EC1 Prev. 'EN'
 
ENB E N Bray Ltd - Waltham Cross, Herts.
 

 
ENS English Steel Corporation - London SW1
 

 
EOA Electric & Ordnance Accessories Co. - Stoke-on-Trent
 
Insulators
EP F W Potter & Sons Ltd - London EC2
 

 
EPB Edgcumbe Peebles Ltd - Bothwell, Lanarkshire
 

 
EPL Enalon Plastics Ltd - Tonbridge, Kent
 

 
EQA Anode Co. Ltd Prev. 'EQ'
 
ER Bonnella Bros. See 'ERA'
 
ERA Fitzgibbon & Murray Ltd - Ewell, Surrey (late Bonnella Bros.) See 'ER'
 
ERM Epoch Radio Manufacturing Co. Ltd
 

 
ERN Erie Electronics Ltd - Tunbridge Wells, Kent.
 

 
ES William Sanders & Co
 

 
ESC Enfield Stone Co. Ltd
 

 
ESF E Shipton & Co. - Northwood Hills, Middx
 

 
ET Baxendale & Co. Ltd - London WC2 Later 'ETA'
 
ETA Baxendale & Co. Ltd - London WC2 Prev. 'ET'
 
EU Burnham & Co. Ltd - Lower Sydenham, London SE26
 

 
EV G W Evans & Co
 

 
EVL Evershed & Vignoles - Acton Lane Works See 'VGA'
 
EW Baxter & Caunter Ltd
 

 
EX C A Carter & Co.
 

 
EY Buckleys (London) Ltd
 

 
EZ Zenith Manufacturing Co. Ltd
 

 
EZA Zenith Electric Co. Ltd - London NW2 Prev. 'EZ'
 
F Post Office Telegraph Instrument Factory - Holloway, London N See 'FH'
 
FAC Fuller Accummulator Co. (1926) Ltd
 

 
FB GPO Factory-Birmingham (Construction) Later 'FBB'
 
FBB Factory-Birmingham (Construction) (GPO/PO/BT) Prev. 'FB'
 
FBC Ferguson Battery Co. Ltd - Slough, Bucks.
 

 
FBR Factory-Birmingham (Repairs) (GPO/PO/BT)
 

 
FC Alex Bruce & Co.- Grays Essex
 

 
FD Hailwood & Ackroyd Ltd
 

 
FE Dubilier Condenser Co. (1921) Ltd See 'DUB'
 
FEL Fidelity Ltd See 'FID'
 
FF Eclat Electric Lamp Manufacturing Co. - London
 

 
FG Burt, Boulton & Haywood Ltd - London
 

 
FGB Sontranic Ltd - Edgware, Middx
 
Answering Machines
FH GPO Factory - Holloway, London N Prev. 'F'; later 'FHB'
 
FHB Factory-Holloway, London N (Construction) (GPO/PO/BT) Prev. 'FH'
 
FHR Factory-Holloway, London N (Repairs) (GPO/PO/BT)
 

 
FID Fidelity Radio Ltd See 'FEL' Hawk Cordless Telephone
FJ The D.P. Battery Co. Ltd Later 'FJA'
 
FJA D P Battery Ltd - Bakewell, Derbyshire Now Electric Power Storage Ltd
 
FJB Elliott Bros.(London) Ltd - Airport Works, Rochester, Kent.
 

 
FJC Elliott Bros.(London) Ltd - Frimley, Aldershot, Surrey
 

 
FJD Elliott Bros. (Radar & Comms Inst Div.) - Stanmore, Middx.
 

 
FJE Elliott Bros. - Hillend, Dumfermline, Fife.
 

 
FJM F J Moore Ltd
 

 
FK Alton Battery Co. Ltd - Alton, Hants.
 

 
FL Accumulators of Woking - Surrey.
 

 
FLC Fortiphone Ltd - Denmark Hill, LONDON SE5
 

 
FM Foster's Machine Tool & Engine Co.
 

 
FMC Calne Electronics - Calne, Wilts.
 
Amplifier 143
FNB Factory-Edinburgh (Construction) (GPO/PO/BT)
 

 
FNR Factory-Edinburgh (Repairs) (GPO/PO/BT)
 

 
FPN AEI Ltd - Bush House, Aldwych, London WC2
 

 
FR Ferranti Ltd - Hollingwood Later 'FRA''
 
FRA Ferranti Ltd - Hollingwood Prev. 'FR'
 
FS The Foster Engineering Co. Ltd
 

 
FT F Tray & Co. Ltd
 

 
FWB Factory-Cwmcarn, Wales (Construction) (GPO/PO/BT) Opened 1950. See 'FWG' Jubilee Compact Telephone
FWG Northern Telecom Europe-Cwmcarn, Wales Was BT Factory. See 'FWB' & 'FWR'.
 
FWM Ferranti - Wythenshawe, Manchester
 

 
FWR Factory-Cwmcarn, Wales (Repairs) (GPO/PO/BT) Opened 1950. See 'FWG'
 
G Believed Salford Electrical Instruments - Lancs. Later 'SEC'
 
GAB Greenwood & Butler - Leeds
 
Meters
GB Jas. Gibbs & Co. Ltd
 

 
GC East & Son Ltd
 

 
GDA Elliott Bros. (London) Ltd - Boreham Wood, Herts.
 

 
GE George Bruce Ltd
 

 
GEB GEC (Electronics) Ltd Computer Divn. - Coventry, Worcs.
 

 
GEC GEC Telephones - Coventry, Worcs.(Opened 1921) Moved from Salford
 
GED GEC/AEI Electronics Ltd - Stanmore, Middx.
 

 
GEG Osram Lamp & Lighting Co. Ltd - Gateshead, Co.Durham Became GEC (Osram) Ltd
 
GEH GEC Ltd - Middlesborough, Yorks.
 

 
GEJ Garratt Engineering Co.
 

 
GEL GEC-AEI Telecomms. Ltd - Accrington, Lancs. (Opened 1970)
 
Relays
GEN GEC-AEI Telecomms. Ltd - Newton Aycliffe, Co. Durham (Opened 1963)
 

 
GEP GEC Telecomms. Ltd - Treforest, Pontypridd
 

 
GER GEC Ltd - Tribune Trading Estate, Rugby
 

 
GET GEC Ltd - Stanmore, Middx.
 

 
GEW GEC Ltd - Wellingborough, Northants.
 

 
GEY GEC (Ash Ltd), Hirst Labs. - Wembley, Middx.
 

 
GF Girlings Ferro Concrete Co. Ltd
 

 
GJ Gillett & Johnston Later 'GJL' Clocks
GJB G Johnson Bros. - London N15
 

 
GJL Gillett & Johnston Ltd - Alperton, Middx. Prev. 'GJ' Clocks
GKT GKN PLC - Telford, Shropshire
 
Kiosks
GM G Mugford
 

 
GNA Pye Scottish Communications - Airdrie (TMC from 1970) See 'TMA'
 
GNT Great Northern Telegraph Works Ltd - Denmark (Founded 1869) Now GN Great Nordic Telegraph instruments
GPL William Geipel Ltd - London SE1 Became Tylec Ltd (TYB)
 
GRO General Relays Ltd - Crewe, Cheshire
 

 
GRR Greengate & Irwell Ltd - Leeds 12, Yorks.
 

 
GS Gillson Syndicate
 

 
GTE GTE
 

 
GTR G.T. Relays Ltd - London EC1
 

 
GZ Doulton & Co. Ltd Later 'GZA'
 
GZA Doulton Industrial Porcelains Ltd - London SE1 Prev. 'GZ'
 
H Automatic Telephone Manufacturing Co. - Liverpool (1911-) Became A.T.E (see 'HAA')
 
HA Hall Telephone Accessories Ltd - London NW10 Later 'HAS' A-B Coinbox
HAA Automatic Telephone & Electric Ltd - Liverpool Was A.T.M; became Plessey
 
HAR Hall Telephone Accessories Ltd
 
A-B Coinbox
HAS Associated Automation Ltd - London NW10 Prev. 'HA' Coinboxes; Telephones
HB Houghton Butcher Manufacturing Co.
 

 
HC British Insulated Cables Ltd (1925-1945) Orig. British Insulated & Helsby Cables. Became BICC (see 'HCA') Cables
HCA BICC Cables - Helsby, Lancs. (from 1945) See 'HC' Cables
HCC BICC - Melling, Nr. Liverpool, Lancs.
 

 
HCL BICC - Leigh, Lancs.
 

 
HCP British Insulated Callender's Cables Ltd - Prescot, Lancs. Was British Insulated Wire Co. Ltd Cables
HD C A & A W Haward
 

 
HDL Hudson's Electronic Devices Ltd - London SW2
 

 
HE H Sloog (Makers of 'Hennite')
 

 
HEA H E Ashdown (Birmingham) Ltd
 

 
HF Eames Brothers
 

 
HFL Hi-Fi Ltd - Old Hill, Staffs.
 
Testers
HG Hart Accummulator Co. Ltd
 

 
HH J E Hough Ltd
 

 
HIG High Grade Instruments Ltd - London NW10
 

 
HIH Higrade Instruments Ltd - London NW10
 

 
HIP Hatfield Instruments Ltd - Plymouth, Devon
 

 
HJ C Hodges & Co. Ltd [later J L Gottlieb & Co. Ltd]
 

 
HK Hillcrete Ltd
 

 
HL Holland & Sons Ltd
 

 
HM Chamberlain & Hookham Ltd
 

 
HN J Hannan
 

 
HND Highton & Sons - Dalston, London E8
 
Pneumatic Tubes
HNL Heath Navigational Ltd - New Eltham London SE9 Was Heath & Co Ltd (see 'heath')
 
HPU Hewlett Packard Ltd - South Queensferry, Edinburgh
 

 
HR Henry Brown & Sons Co - Luton Later 'HRA'
 
HRE Haslemere Radio & Electricals - Haslemere, Surrey.
 

 
HRH Hertford Relays Ltd - Hoddesden, Herts. See 'HRO'
 
HRM Howells Radio Ltd - Manchester
 

 
HRO Hertford Relays Ltd - Crewe, Cheshire See 'HRH'
 
HS Howells & Co.
 

 
HSB Howells & Co. - Sheffield See 'HS'
 
HT A W Hart
 

 
HTP Hewlett Packard Ltd - Slough, Bucks.
 

 
HV Hivac Ltd - Ruislip, Middx. Became part of Plessey (see 'HVA')
 
HVA Plessey Hivac Division- Ruislip, Middx. Formerly Hivac Ltd ('HV')
 
HVB Hivac Ltd - Harrow, Middx Became part of Plessey (see 'HVA')
 
HVC Hivac Ltd - Chesham, Bucks. Became part of Plessey (see 'HVA')
 
HVR Hivac Ltd - Ruislip, Middx. See 'HV' & 'HVA'
 
HY G A Harvey & Co. Ltd
 

 
I International Electric Co. Ltd - London Previously Anglo-Austrian Brush Electrical Company Telephones; Switchboards; Cables
IA British Die-Casting & Engineering Co. - New Barnet, Herts.
 

 
IAL International Aeradio Ltd - Southall, Middx.
 

 
IB G H Bartlett & Co. - London SW16
 

 
IBX Ibex Telephones - London NW6 (later Ibex Electronics Ltd)
 

 
ICA International Computers & Tabulators Ltd - Letchworth
 

 
IEA Instruments Electrical Ltd - London SE1
 

 
IEC International Electric Ltd ?? Same firm as 'I'
 
IGE Witton Moulded PLastics Ltd - Birmingham 6 Part of GEC.
 
IM Imperial Typewriter Co. Later 'IMP'
 
IML Injection Moulders Ltd - London NW9
 

 
IMP Imperial Typewriter Co. Prev. 'IM'
 
IMR International Marine & Radio Co. Ltd - Croydon
 

 
INE Insulators Ltd - London
 

 
INS Insulators Ltd - Paddock Wood, Kent
 

 
IT International Time Recorder Co.
 

 
ITI Indian Telephone Industries - Bangalore, India
 

 
ITS International Computers & Tabulators Ltd - Oldham
 

 
JA J A Crabtree & Co. Ltd
 

 
JB B W Johnson - Stroud, Glos.
 

 
JC J Chesterman & Co. Ltd
 

 
JGS Switchgear Ltd
 

 
JKA Brooker & Jackson Ltd - London N1 Prev. 'JK'
 
JM J McKenzie & Co.
 

 
JMC Johnson Matthey & Co. - Burslem, Staffs.
 

 
JNA John Norman Ltd
 

 
JNW Jones & Nathan Ltd - Watford, Herts.
 

 
JPA Josiah Parkes & Sons Ltd - Willenhall, Staffs.
 

 
JSA J & E Bates & Sons Ltd - Wolverhampton
 

 
JX Julius Sax & Co. Ltd Later 'JXA'
 
JXA Julius Sax & Co. Ltd - Brentford, Middx Prev. 'JX'
 
K Kelvin, Bottomley & Baird Ltd
 

 
KB K E Beswick - Frome, Somerset Later 'KBA'
 
KBA K E Beswick - Frome, Somerset Prev. 'KB'
 
KC E A Combs Ltd - London EC1
 
Clocks & Watches
KCP Kent Concrete Products Co.
 
Kiosk No3
KD J Cadman & Co. Ltd
 

 
KE Chloride Electrical Storage Co. Ltd See 'KEA'
 
KEA Electric Power Storage Co. - Swinton, Manchester See 'KE'
 
KEC E K Cole Ltd - Rochford, Essex (later EKCO Avionics)
 

 
KFA Kent Mouldings - Sidcup, Kent.
 
Mouldings
KJ J Crombie & Son
 

 
KKA E K Cole Ltd - Southend, Essex See 'PTE'
 
KKM E K Cole Ltd - Malmesbury, Wilts. See 'PTE'
 
KL The Crypto Electrical Co. Ltd
 

 
KLA Lancashire Dynamo & Crypto Ltd - Trafford Park, Manchester
 

 
KM The Camelinat Co.
 

 
KNE K & N Electronics Co.Ltd - Maidenhead, Berks.
 

 
KQ Craig Lelo Quarry Co. Ltd
 

 
KR Cryselco Ltd
 

 
KRN Krone(UK)Technique Ltd - Cheltenham
 
Versatel Telephone
KS Carver & Son
 

 
KT Croft Granite, Brick & Concrete Co. Ltd
 

 
KU The Concrete Unit Co. Ltd
 

 
KZ L Keizer & Co. Ltd
 

 
L Elliott Bros.(London) Ltd - London SE13 Later 'LEB'
 
LAB Labgear Ltd - Cambridge
 

 
LAT Latimer Engineering Co. - London W10
 

 
LBG Simplex Electricals Co Ltd - Birmingham
 

 
LDA Cossor Communications Co. Ltd - Stanmore, Middx.
 

 
LDI Llandis & Gyr - Dublin
 
Minimaster 3
LE Litholite Insulators & Mouldings Ltd - Worthing Later 'LEA' Mouldings
LEA Litholite Insulators & Mouldings Ltd - Worthing Prev. 'LE' Mouldings
LEB Elliott Bros.(London) Ltd - Century Works, Lewisham London SE13 Prev. 'L'
 
LED Gresham Lion Electronics Ltd - Hanworth, Middx.
 

 
LEL Level Electronics Ltd - High Barnet, Herts.
 

 
LER Lero Engineering Company - Coventry (Formed 1941)
 

 
LEW London Electric Wire Co. Ltd - Leyton, London E10 Became GEC Optical Fibres Cables
LF Lion Foundry - Kirkintilloch, Glasgow Later 'LFA' Kiosks; Cross Connexion Cabinets
LFA Lion Foundry - Kirkintilloch, Glasgow Prev. 'LF' Kiosks; Cross Connexion Cabinets
LGA Landis & Gyr Ltd - London W3
 

 
LK W & T Lock Ltd
 

 
LN Lissen Ltd
 

 
LP Lindsay, Parkinson & Co. Ltd
 

 
LR Thomas De La Rue - Walthamstow, London E17 Later 'LRA' Mouldings
LRA De La Rue & Co. Ltd - West Chirton, North Shields, Northumberland Prev. 'LR'; see also 'DRP' Mouldings
LS Lang & Squire Ltd
 

 
LSE Laurence Scott & Electromotors Ltd - Norwich
 
Ringing Machines
LSM Laurence Scott & Electromotors Ltd - Manchester
 
Ringing Machines
LUC Joseph Lucas Ltd - Birmingham
 

 
LUS Lustraphone Ltd - London NW1
 

 
LVA Lorival Ltd - Bolton, Lancs.
 

 
LWA Lightwood & Son - Birmingham
 

 
M W Maxwell & Co. Ltd Later 'MWM'
 
MA Males & Andrews Ltd Later 'MAA'
 
MAR Marconi Wireless Telegraph Co. - Gt. Baddow
 

 
MBA MacFarlane, Burchall & Co.
 

 
MBD Mallory Batteries Ltd - Crawley, Sussex.
 

 
MCA Peter McAinch Ltd
 

 
MCL Morgan Crucible Co. Ltd - London SW11 Now Morganic Resistors Ltd
 
MD B.D. & Co Ltd - London EC1 Later 'MDA'
 
ME F W Male & Son Ltd
 

 
MF Walter Macfarlane & Co. - Glasgow Later 'MFA' Kiosks
MFA Walter Macfarlane & Co. - Glasgow Prev. 'MF'
 
MH A G Matthews
 

 
MIC Micanite & Insulators Co Ltd - London E17
 

 
MK Marconi Scientific Instrument Co.
 

 
MKE W Mackie & Co. See 'MWO' Dynamotors
ML C A Middleton Ltd
 

 
MM Condenser & Electrical Co.
 

 
MN Metropolitan Vickers Electrical Co. Ltd See 'MNA'
 
MNA AEI Ltd - Wythenshawe, Manchester See 'MN'
 
MOR Morganite Resistors Ltd - Jarrow, Co. Durham
 

 
MOV M.O. Valve Co. Ltd - Hammersmith, London W6
 

 
MP Moulded Products Ltd - Birmingham Later 'MPA'
 
MPA Moulded Products Ltd - Tyburn, Birmingham Prev. 'MP; see 'MPM'
 
MPB Mullard Blackburn Works Ltd - Blackburn, Lancs.
 

 
MPC Mitcham Works Ltd - Mitcham, Surrey
 

 
MPD Mullard Ltd - London SW17
 

 
MPF Phillips Balham Works - London SW2
 

 
MPM Moulded Products Ltd - Colne, Lancs. See 'MPA'
 
MRG Maines Radio Gramophones Ltd
 

 
MRL McMichael Ltd - Slough, Bucks.
 
Radio Equipment
MRO Masteradio Ltd - Slough, Bucks.
 

 
MRR Mullard Research Labs. - Salford, Lancs.
 

 
MS Mead Ltd Later 'MSA' Kiosks
MSD Microwave Systems Ltd - Scotland
 

 
MSL McDowell Steven & Co. - Falkirk, Stirlingshire
 
Kiosks
MT Moore & Wright Ltd - Sheffield, Yorks.
 

 
MTC Millar's Timber & Trading Co. Ltd
 

 
MTF Mount Electronics Ltd - London N3
 

 
MTO Modern Telephones Ltd - London NW2 See 'MTW'
 
MTW Modern Telephones Ltd - London SW19 See 'MTO'
 
MU Murray (c/o Reid Bros.) Later 'MUA'
 
MUL Mullard Radio Valve Co. Ltd - Saltford, Lancs. (Formed 1920) Prev. 'MV'
 
MUO Mullard Ltd - London WC1
 

 
MUR Murphy Radio Ltd - Welwyn Garden City, Herts.
 

 
MUW Mullard Radio Valve Co. - Whyteleafe, Surrey. (Opened 1932) See 'MV' & 'MUL'
 
MV Mullard Radio Valve Co. Ltd - Saltford, Lancs. (Formed 1920) Later 'MUL'
 
MW Mickelwright Ltd - Alperton, Wembley, Middx.
 

 
MWB Marconi Wireless Telegraph Co. - Basildon, Essex Became Marconi Co. Ltd
 
MWH Marconi Wireless Telegraph Co. - Wallington, Surrey Became Marconi Co. Ltd
 
MWM W Maxwell & Co. Ltd Prev. 'M'
 
MWO W Mackie & Co. - Mitcham, Surrey See 'MKE'
 
MWW Marconi Co. Ltd - Witham, Essex.
 

 
MXB Motorola - Basingstoke, Hants.
 
Radiopagers
N Nalder Bros. & Co. Ltd See 'AC'. Acquired by Muirhead & Co.
 
NAA Nalder Bros. & Co. Ltd See 'AC'. Acquired by Muirhead & Co.
 
NB Newton Brothers (Derby) Ltd
 
Dynamotors
NE North of England School Furnishing Co.
 

 
NJ British Nigerian Timber Co.
 

 
NPC British Moulded Plastics - London E4
 

 
NS Neil Small & Co. - Kilwinning, Ayrshire
 

 
NSF N.S.F. Ltd - Keighley, Yorks.
 

 
NW Norwest Construction Co. Ltd
 

 
O Gent & Co. - Leicester (Formed 1872) Later 'OAA'
 
OAA Gent & Co. Ltd - Leicester (Formed 1872) Prev. 'O'. Now Caradon Gent Ltd.
 
OD D M Davies Ltd - Sunbury-on-Thames
 

 
OLA Oldfield Ltd - Bordersley, Birmingham
 

 
OLL Omega Lamp Works - New Malden, Surrey.
 

 
OM Oldham & Son
 

 
P R W Paul
 

 
PA Parkes Samuel & Co. Ltd - Willenhall, Staffs.
 

 
PBE Plessey Co. Ltd - Liverpool 2
 

 
PBI Plessey (NI) Ltd - Ballynahinch, Co. Down.
 

 
PCA PCA Radio Ltd - London W6
 

 
PCB Plessey - Whiteside Works, Bathgate, West Lothian See 'PLF'
 
PCC Pioneer Circuits Ltd - Havant, Hants.
 

 
PE Power Equipment Co. - Birmingham Later 'PEC'
 
PEA Precision Electronic Terminations Ltd - Sevenoaks, Kent.
 

 
PEC Power Equipment Co. - Birmingham Prev. 'PE'
 
PER Plessey Electrical Equipment Divn.- Romford, Essex
 

 
PET Precision Electronic Terminations Ltd - Sevenoaks, Kent. See 'PEA'
 
PF PLanet Foundry Co. Ltd - Manchester Later 'PFC'
 
PFC PLanet Foundry Co. Ltd - Manchester Prev. 'PF'
 
PG Pitter Gauge & Precision Tool Co. - Woolwich, London SE18 Later 'PGP'
 
PGH Pirelli - Eastleigh, Hants.
 

 
PGL Pirelli - Southampton
 

 
PGP Pitter Gauge & Precision Tool Co. - Woolwich, London SE18 Prev. 'PG'
 
PH W G Pye & Co. - Granta Works, Cambridge
 

 
PIC Papworth Industries - Cambridge
 

 
PIM Premier Injection Mouldings Ltd - Lewes, Sussex.
 
Mouldings
PK Charles Peacock & Co
 

 
PL Plessey - Ilford, Essex (1921- Later 'PLA'
 
PLA Plessey - Ilford, Essex (1921- Prev. 'PL' Telephone
PLC Poles Ltd - Erdington, Birmingham
 

 
PLF Plessey - Whiteside Works, Bathgate, West Lothian See 'PCB'
 
PLS Plessey - Kemberry Rd, Swindon, Wilts.
 

 
PLU Plessey - Upminster, Essex
 

 
PLV Plessey - Havant, Hants.
 

 
PLW Plessey - Chaney Manor, Swindon, Wilts.
 

 
PLX Plessey - Newport, Gwent
 

 
PMA Parmeko Ltd - Leicester Prev. 'PM'
 
PMC A.T.E. (Wigan) Ltd - Pioneer Works, Wigan, Lancs. Became Plessey (Speke Telephones)
 
PML Automatic Telephone & Electric Ltd - Chorley, Lancs. (Later Plessey)
 

 
PN Radio, Phonopore & Electricals Ltd - Southall, Middx Later 'RNA'
 
PP Pearce & Partners, Tees Foundries Ltd - Middlesborough Later 'PPL'
 
PPL Pearce & Partners, Tees Foundries Ltd - Middlesborough Prev. 'PP'
 
PR Premier Accumulator Co. - London SW1
 

 
PRW Cambridge Instruments Ltd - Cambridge
 

 
PS Parkside Engineering Co. Ltd Later 'PSB'
 
PSB Parkside Engineering Co. Ltd Prev. 'PS'
 
PSD Plessey - Dublin, Ireland
 

 
PSL Poulton Selfe & Lee Ltd - Wickford, Essex
 

 
PTE Pye Telecomms. Ltd - Ekco Works, Southend, Essex See 'KKA'
 
PTL Pye Telecomms. Ltd - Haverhill, Suffolk
 

 
PTN Reliance Telephone Co. Ltd - Birmingham
 

 
PW Palmer & Waumsley Ltd
 

 
PX Phoenix Telephones & Electric Works Ltd - London NW9 Later 'PXA' Candlestick Telephones
PXA Phoenix Telephones & Electrical Ltd - London NW9 Prev. 'PX' Candlestick Telephones
PY Pyne Manufacturing Co.
 

 
PYE Pye Telecomms. Ltd - Cambridge See 'CWL'
 
PYI Pye Radio Ltd - Cambridge
 

 
PYL Pye Radio Ltd - Leicester
 

 
PYN Portadyne Radio Ltd
 

 
PYT Plessey - Taplow, Maidenhead, Berks.
 

 
PZA Pritchetts Gold & EPS Co. Ltd, & Alton Battery Co. - Dagenham Dock, Essex Prev. 'PZ'
 
R Reid Brothers (Founded 1813 as William Reid) See 'RBA'
 
RA Radio Instruments Ltd
 

 
RAA Llandis & Gyr (formerly Aeronautical & General)
 
Payphones
RAC Racal Communications Ltd - Bracknell, Berks. See 'RCJ'
 
RAJ Racal Communications Ltd - Bracknell, Berks. See 'RAC' & 'RCJ'
 
RAW Roberts & Armstrong (Engineers) Ltd - Wembley, Middx
 
Speaking Clock
RBA Reid Brothers Engineers (1860c-1921c) Same as W Reid & Co.?
 
RBB Rival Lamps Ltd - Weybridge, Surrey
 

 
RC Ross Courtney & Co. Ltd - London N19
 

 
RCJ Racal Communications Ltd - Bracknell, Berks.
 

 
RCM Radio Communications Ltd
 

 
RD W M Richmond & Co. Later 'RDB'
 
RDB W M Richmond & Co. Prev. 'RD'
 
RDC Radio Development Co.
 

 
RH Ruston & Hornsby Ltd - Birmingham
 

 
RIA Rathdown Industries Ltd - Ascot, Berks.
 

 
RIC Racal Instruments Ltd - Crowthorn, Bucks. See 'RAC' & 'RCJ'
 
RLA Ryford Ltd - Aldridge, Staffs.
 

 
RLE Ripaults Ltd - Enfield, Middx
 
Cords
RMA Radio Mart (G5N1) Ltd - Birmingham
 

 
RMG Reliance Manufacturing Co. - London SE
 

 
RML Rotheroe & Mitchell Ltd - Greenford, Middx.
 

 
RNA Radio, Phonopore & Electricals Ltd Prev. 'PN'
 
RON Roneo Ltd - Romford, Essex.
 

 
RR R Robertson Ltd
 

 
RRC Rolls Razor Ltd - Cricklewood, London NW2
 

 
RS Radio Supplies Ltd
 

 
RSA Radio Supplies Ltd Prev. 'RS'
 
RT Robert Edwards Ltd
 

 
RTL Racal Transcom Ltd - Salisbury, Wilts.
 
Transactionphone
RTN Reliance Telephone Co. Ltd - Birmingham
 

 
RV Revco Electric Co. Ltd
 

 
S Siemens Bros.- Woolwich, London SE18 (Opened 1863) Became A.E.I (see 'SEG')
 
SA Saunders Electrical Co.
 

 
SAF Shipton Automation Mfg Co Ltd - Hemel Hempstead, Herts.
 

 
SAP South African Porcelain Insulator Manufacturing Assn. - London WC1
 

 
SAV Savage Transformers Ltd - Devizes, Wilts.
 

 
SB S G Browns Ltd - Watford, Herts
 

 
SBD Stonebridge Electrical Co. Ltd
 

 
SBL Sterling Batteries Ltd
 

 
SBM Salford Electrical Instruments - Manchester
 

 
SC Smith L.C. & Corona Typewriters Ltd
 

 
SCC Static Condensers Co. Ltd - Wokingham, Berks.
 

 
SCD Standard Insulator Co. Ltd - Camberley, Surrey
 

 
SCF Marconi Co Ltd - Gateshead
 

 
SCL Marine Submarine Cables Ltd - Erith
 

 
SCP Surrey Concrete Products Ltd
 

 
SD S Davall & Sons Ltd - Greenford, Middx.
 

 
SE Small Electric Motors Ltd Later 'SEM'
 
SEA Siemen-Edison Swan - London N17 Became A.E.I.
 
SEB Stanford Engineering Ltd - London SW1
 

 
SEC Salford Electrical Instruments - Heywood, Lancs. (part of GEC) See 'SET' & 'SBM'
 
SED Startall Equipment Ltd - Staines, Middx.
 

 
SEG AEI Ltd - Woolwich, London SE18 (ex Siemens) See 'S'
 
SEI Sifam Electrical Instrument Co. Ltd - Torquay
 
Meters
SEL AEI Ltd - Lamps & Supplies, Brentford, Middx.
 

 
SEM Small Electric Motors Ltd - Beckenham, Kent Prev. 'SE'
 
SER AEI Ltd - West Hartlepool, Co.Durham (ex Siemens)
 
Exchange Relays
SET Salford Electrical Instruments Ltd - Stockport, Cheshire See 'SEC' & 'SBM'
 
SEW Siemen- Edison Swan - Woolwich, London SE18 See 'SEA'
 
SF Schofield & Flexton Ltd Later 'SFA'
 
SFA Schofield Preston & Co. Ltd - Nelson, Lancs. Prev. 'SF'
 
SFC Standard Fuse Co. - Ponders End, Enfield, Middx.
 

 
SFR Storno Ltd - Camberley, Surrey
 

 
SG George Salter & Co. Ltd - West Bromwich, Staffs. Later 'SGC'
 
SGC George Salter & Co. Ltd - West Bromwich, Staffs. Prev. 'SG'
 
SGL Silica Gel Ltd - Hounslow, Middx.
 

 
SGY AEI Ltd - Wembley, Middx. (Ex. Siemens)
 

 
SHA Streetley Manufacturing Co. Ltd - Sutton Coldfield, Warwicks. Mould designers Compact Telephone
SHR Siemens & Halske - Germany (founded 1847)
 

 
SID Salmon Industries Ltd - Northern Ireland
 
Duct covers
SIG Sign Electronics Ltd - London SE18
 

 
SIW Smiths Industries Ltd - Witney, Oxon.
 
Dials??
SKY Jos. Sankey & Son Ltd
 
Diaphragms
SL H J Leak & Co. Ltd - Bradford, Yorks. Later 'SLC'
 
SLC H J Leak & Co. Ltd - Bradford, Yorks. Prev. 'SL'
 
SLW Speke Telephones Ltd - Wigan, Yorks. See 'SPK'
 
SM Stuart & Moore (taken over by G Longfield-Beasley)
 

 
SMA Longfield Beasley Ltd
 

 
SN Solidite & Synthetic Mouldings Ltd
 
Mouldings
SNL Smith Newall Lamp Works
 

 
SP Small Power Dynamo & Motor Co. Ltd
 

 
SPB Southern Instruments (Communications) Ltd - Camberley, Surrey Became Ansafone (See 'ANS')
 
SPG Sperry Gyroscope Co. Ltd - Brentford, Middx.
 
STD Magnetic Drum
SPH Sperry Gyroscope Co. Ltd - Bracknell, Berks.
 
STD Magnetic Drum
SPI Sperry Gyroscope Co. Ltd - Stonehouse, Glos.
 
STD Magnetic Drum
SPK Speke Telephones Ltd - Speke, Liverpool See 'SLW'
 
SPP Steatite & Porcelain Products - Stourport-on-Severn
 

 
SR Estler Brothers
 

 
SRY Sterling Cables Ltd - Aldermaston, Berks.
 

 
SS Ebonestos Insulators Ltd - London SE15 Later 'SSA' Mouldings
SSA Ebonestos Industries Ltd - London SE15 Prev. 'SS'. Note name change. Mouldings
SSG Splintex Safety Glass Co - London W7
 
Glass in Kiosks
SSL Siemens-Shuckert (G.B.) Ltd - Brentford, Middx.
 

 
SSS Smith's Industrial Instruments Ltd - London NW1 (Formerly S Smith & Sons [Motor Accessories] Ltd)
 

 
ST Stuart Turner Ltd
 

 
STC STC - New Southgate, London N11 (1925 on) Became Northern Telecom Telephone
STD STC Industrial Supplies - Foots Cray, Kent
 
Tower Models
STE STC (Valve Divn.) - Paignton, Devon
 

 
STI STC - Ilminster, Somerset
 

 
STJ STC - Harlow, Essex
 

 
STK STC Rectifiers - Boreham Wood, Herts.
 

 
STL Standard Telecomms. Labs. - Harlow, Essex
 

 
STM STC - Monkstown, N.Ireland
 
Telephones
STP STC - Monkstown, N.Ireland
 

 
STU STC - Enfield, London N
 

 
STW STC - Taunton, Somerset
 

 
STZ STC - Newport, Mon.
 

 
SU The Educational Supply Association Ltd
 

 
SUE Submarine Cables Ltd - Erith, Kent (From 1954) See 'SCL' Submarine Cables
SUG Submarine Cables Ltd - Greenwich, London SE3 (Formed 1935) See 'DJA' & 'S' Submarine Cables
SUN Submerged Signal Co.
 

 
SV D G Somerville & Co. Ltd
 

 
SVA D G Somerville & Co. Ltd Prev. 'SV'
 
SY H C Slingsby - Liverpool
 

 
T Tyer & Co. - Nottingham
 

 
TA Thermega Ltd
 

 
TAB Trojan Accum Co. - Watford, Herts.
 

 
TAC Tyer & Co. See 'T' & 'TAS'
 
TAD Tallent Engineering Ltd - Darlington
 

 
TAL Turner Asbestos Cement Co. - Manchester
 
Insulators
TB Turner Brothers Ltd
 

 
TBE Telerelays Sales Ltd -Braintree, Essex
 
Exchange Relays
TBK Thurgar Bolle Ltd - Kettering, Northants.
 
Glass 81A
TCB Telegraph Condensor Co. Ltd - Bathgate
 

 
TCC Telegraph Condensor Co. Ltd - Birmingham
 

 
TCD Telephone Cables Ltd - Dagenham, Essex
 

 
TCE STC - Enniskillen, N.Ireland
 
Telephones; switchboards
TCH STC - Corran Works, Larne, N.Ireland (closed 1976)
 
Telephones; Headsets
TCL Trent Concrete Ltd
 

 
TCON Team Concepts International Ltd (Hong Kong)
 
Robin Answering Machine
TCP STC - Leeds
 

 
TCS STC (Electronic Switching Divn.) - Southgate, LONDON N14
 

 
TD H J Townsend
 

 
TE Telephone Manufacturing Company (Formed 1914) Later 'TEA'
 
TEA TMC - Dulwich, London SE21 (Formed 1914) Prev. 'TE'
 
TES TMC - St Mary Cray, Kent (Opended 1939)
 

 
TEW TMC - Winford, Cheshire
 

 
TF Timber Fireproofing Co. Ltd
 

 
TG Tungstone Accumulator Co. Ltd
 

 
TGA Tungstone Products Ltd - London EC4 Prev. 'TG'
 
TGR Thorn Ericsson - Rochester, Kent
 

 
TGW Thorn Ericsson - Scunthorpe
 

 
TH The British Thomson-Houston Co.
 

 
TK The Bradford Patent Truck & Trolley Co.
 

 
TL Eastern Telegraph Co. See 'TLA'
 
TLA Cables & Wireless Ltd - London WC1 See 'TL'
 
TLB Thomas William Lench Ltd - Birmingham
 

 
TM Telephone & Microphone Co. Later 'TMC'
 
TMA TMC - Airdrie, Lanarkshire See 'GNA'
 
TMC Telephone & Microphone Co. Prev. 'TM'
 
TME [not known]
 

 
TMK TMC - King's Lynn, Norfolk
 

 
TMM TMC - Malmesbury, Wilts.
 

 
TMR Thomas Glover & Co. - Hillington Industrial Estate - Glasgow
 

 
TN J W Thomson Ltd
 

 
TP Thornton Pickard Manufacturing Co. Later 'TPM'
 
TPC TMC Transmission Divn - St.Mary Cray, Kent
 

 
TPF Telcon Plastics Ltd - Orpington, Kent See 'DJA'
 
TPH Thermionic Products Ltd - Hythe, Hants.
 

 
TPM Thornton Pickard Manufacturing Co. Prev. 'TP'
 
TR Ernest Turner Electrical Instruments Ltd - High Wycombe Later 'TRA' Meters
TRA Ernest Turner Electrical Instruments Ltd - High Wycombe Prev. 'TR' Meters
TRB Richard Thomas & Baldwin Ltd
 
Diaphragm
TS The Thames Manufacturing Co. Ltd
 

 
TSD Telephone Supplies Ltd - Aycliff, Co.Durham
 
Dials
TT Taylor Tunnicliff & Co. Ltd - Lastwood, Hanley, Staffs. Later 'TTC' Insulators
TTC Taylor Tunnicliff & Co. Ltd - Lastwood, Hanley, Staffs. Prev. 'TT' Insulators
TTH TMC - Canterbury, Kent
 

 
TTL TMC - Livingstone, Bathgate, West Lothian (Opened 1969)
 

 
TU Tudor Accumulator Co. Ltd Later 'TUD'
 
TUD Tudor Accumulator Co. Ltd (D.P. Batteries) - Dukinfield, Cheshire Prev. 'TU'
 
TW Tate & Wilkinson Ltd
 

 
TY H Tinsley & Co. Later 'TYA'
 
TYA H Tinsley & Co. - London SE25 Prev. 'TY'
 
U Walter's Electrical Manufacturing Co. Ltd - London (Formed 1880) Later 'UAA'
 
UAA Walter's Electrical Manufacturing Co. Ltd - London (Formed 1880) Prev. 'U'
 
UC United Insulator Co. - Chessington, Surrey
 

 
UG United Woodworking Co. Ltd - Oxford
 

 
UME Multitone Ltd
 
Radiopagers
US United Steel Companies Later 'USB'
 
USB United Steel Companies Prev. 'US'
 
UW Underwood Portable Typewriters Ltd
 

 
VA The Varley Magnet Co. Later 'VAB'
 
VAA T Watson Ltd
 

 
VAB The Varley Magnet Co. - London SE18 Prev. 'VA'
 
VD Ever- Ready Co.(G.B.) Ltd - London N7 See 'EBD'
 
VG Evershed & Vignoles Ltd - London W4 Later 'VGA'
 
VGA Evershed & Vignoles Ltd - London W4 Prev. 'VG'. See 'EVL'
 
VK Vickers Ltd Later 'VKB'
 
VKB Vickers Ltd Prev. 'VK'
 
VKG Viking Connectors (UK) Ltd - Barton-le-Clay, Beds.
 

 
VLC Varta Ltd - Crewkerne, Somerset
 
Batteries
VN Venesta Ltd - London E16
 

 
VS Evans Brothers Ltd
 
Concrete
VTS Venner Time Switches - New Malden, Surrey
 

 
VV C A Vandervell & Co. Ltd
 
Batteries
VW Visible Writing Machine Co. Ltd
 

 
VWL W Vinten Ltd
 

 
W Standard Telephones & Cables Ltd - North Woolwich, London (Western Electric pre 1925) Later 'WAA'
 
WAA STC - North Woolwich, London E Prev. 'W'
 
WAB STC - Newport, S. Wales
 

 
WAE STC - Basildon, Essex
 

 
WAS STC - Southampton
 

 
WB Westinghouse Brake & Saxby Signal Co. Ltd
 

 
WBW Wire Broadcasting Workshops (GPO)
 

 
WC Walsall Conduits Ltd
 

 
WCP Weston Electric Instruments Ltd Prev. 'CP'
 
WE Weatherlite Ltd
 

 
WER Whiteley Electrical Radio - Mansfield, Notts.
 
Dials;
WF W H Foster & Sons
 

 
WG Ward & Goldstone Ltd - Manchester
 

 
WGB Wright Brindley & Gell Ltd - Birmingham
 

 
WH William White & Co. Ltd - London (Electrical Engineers)
 

 
WJ Walter Jones & Co. Ltd Later 'WJA'
 
WJA Walter Jones & Co. Ltd Prev. 'WJ'
 
WJH Walter Instruments Ltd - Morden, Surrey
 

 
WJM Wilkinson J A Ltd - Sheffield
 
Tools
WK L Weekes Ltd
 

 
WKF Waterlow-Kingsbury Ltd - London EC2
 

 
WL David Willetts Ltd
 

 
WLC Walsall Locks & Cart Gear Ltd - Walsall
 
Locks on Coinboxes
WN W Wesson & Co. (Steel Manufacturers)
 

 
WR Weir Electrical Instruments Co. Ltd
 

 
WS M W Woods
 

 
WT Wellington Tube Works Ltd - London SW1
 

 
WTB Wireless Telephone Co. Ltd - Sheffield
 

 
WW Wilson Wolf Engineering Co. Ltd
 

 
WWI Webb & Wells - Ilford, Essex
 
Telephones
X Wilcox Ltd Later 'XAA'
 
Y W Wilson Later 'YAA'
 
Z Negretti & Zambra - Aylesbury, Bucks. Later 'ZAA'
 
ZE Zenith Watch Co. Ltd (GB) Later 'ZEA' Clock 33
ZEA Zenith Watch Co. Ltd (GB) Prev. 'ZE'
 


Moulding marks

BLD or BLtd     Birkby's of Liversedge (W. Yorks.), the plastics moulding division of Plessey.

C                GEC Ltd (Telephone Works, Coventry)

G                GEC Ltd

LR              Thomas De La Rue Ltd,

MPL           Moulded Products Ltd

S                 Siemens Brothers Ltd.

 

Title numbers
All BPO telephone sets (also equipment large and small) carried a ‘title number’, in which table telephones, portable telephones and piece parts such as handsets carried even numbers whilst wall telephones had odd numbers.  Special and experimental telephones had numbers prefixed SA (Subscribers’ Apparatus), whilst designs inherited from the former National Telephone Company were prefixed NT.

As well as the title number, telephones normally carried a mark number and the date of manufacture. The original design is known as Mark 1, the first modification as Mark 2 and the second as Mark 3 (and so on). Earlier on original designs and modifications were identified by three digits, starting with 234, for the original design, then 235 for the first modification, 236 for the second modification and so on. 

Examples:  Telephone 162 C34/1 indicates title number 162, made by GEC in 1934 to the Mark 1 design.  Under the older scheme of marking this would have been shown as

 C34    No. 162
 234

Moulded items carried a letters and number code in which the upper two letters indicated the item manufacturer, the lower two letters the moulding subcontractor and the numeral the type of moulding material.

Non-BPO codes

British Codes
Note that type numbers of telephones beginning AP or Z are not BPO codes. AP stands for Admiralty Pattern, denoting a Royal Navy design, and YA and ZA are British Army prefixes. A pattern number starting 10A (or 10 followed by another letter) is Ministry of Defence. Type numbers beginning H are generally ATE products (the company originated at the place of Helsby), N denotes British Ericsson products, S are Siemens Brothers or AEI numbers, TEL is normally GEC, whilst a number beginning SA on BPO instruments denotes Subscribers’  Apparatus, generally a pre-release prototype or an item made specially for a particular customer.

Australian PMG manufacturer codes
Manufacturer codes were allocated by the Postmaster General are generally as for the BPO, with the addition of B.I. and B.I.H., which both indicate British Insulated Cables Ltd, located at Helsby. The ATM company was a spin-off of B.I. which itself merged with Callander’s Cables Ltd and became BICC.

New Zealand
Some telephones made for the New Zealand Post Office carried the initials HCUNZ, standing for H.C. Urlwin of Christchurch, New Zealand.

 
 
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Last revised: March 19, 2018

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