Click here for Moulding markings

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 Letters

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

AGP Armstrong Gregory Plastics - Southend

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' Became GEC
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

AS Noakes & Sons    
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'
B Ltd Birkby's Ltd
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
BX Williamson Clock Co. Ltd

BY G Welch & Sons  
C GEC Telephone Works Ltd (late Peel-Conner Co.) - Salford (1908-1921c) Moved to Coventry in 1921 (see 'GEC') Mouldings as well
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

CL Prison Commissioners of Scotland    
CLB Ceag Ltd - London SW1
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
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'
EI Unknown   Kiosk K6 Backboard
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

EMT EMI   Dial No. 54 and Privacy Set No. 8
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
EP F W Potter & Sons Ltd - London EC2

EPB Edgcumbe Peebles Ltd - Bothwell, Lanarkshire

EPL Enalon Plastics Ltd - Tonbridge, Kent

EQ Anode Co. Ltd  
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)

Repaired apparatus
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)
repaired apparatus
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 Salford Electrical Instruments - Lancs. Later 'SEC'
GAB Greenwood & Butler - Leeds
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)
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
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


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.
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

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

JMC Johnson Matthey & Co. - Burslem, Staffs.

JN John Norman Ltd  
JNA John Norman Ltd

JNW Jones & Nathan Ltd - Watford, Herts.

JPA Josiah Parkes & Sons Ltd - Willenhall, Staffs.

JR Joseph Rymolds  
JS J & E Bates  
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

KA Calders 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.
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

MPL Moulded Products Ltd
Used on mouldings
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
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.
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
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.

NTC Northern Telecom   Telephones & Systems
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.

PC H.M. Prison Commissioners  
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.
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.

PZ Pritchetts Gold & EPS Co. Ltd  
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)
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.

RE Reliable Engineering  
RF Royal Gun & Carriage factories  
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
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.
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
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.
SKY Jos. Sankey & Son Ltd
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
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
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
TB Turner Brothers Ltd

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

TCC Telegraph Condenser 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 (Opened 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
TS The Thames Manufacturing Co. Ltd

TSD Telephone Supplies Ltd - Aycliff, Co.Durham
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

UEO Uplec Electronics - Wrexham
UG United Woodworking Co. Ltd - Oxford

UME Multitone Ltd
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
VN Venesta Ltd - London E16

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

VV C A Vandervell & Co. Ltd
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

WEE Wilson Wolf Engineering Co, Ltd  
WER Whiteley Electrical Radio - Mansfield, Notts.
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
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
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'


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.


Moulding Products
Code Letters allocated to Manufacturers

Code Manufacturer
BLD or BLtd Birkby's of Liversedge (W. Yorks.), the plastics moulding division of Plessey
C GEC Ltd (Telephone Works, Coventry)
CL Unknown
D Unknown
E Ericsson Telephones Ltd (Beeston)
KKK E. K. Cole
LR Thomas De La Rue Ltd
M Melamine
MPL Moulded Products Ltd
S Siemens Brothers Ltd
TE Telephone Manufacturing Co. (TMC)
W Unknown
WC Unknown

Code Numbers for Moulding Material

Code Number Moulding material
1 Bakelite
11 Acrylonitrile Butadiene Styrene
12 Perspex (Polymethyl Methacrylate)
16 Toughened Polystyrene
17 ABS

Moulded items are marked with a manufactures code.  Where manufacturers supply moulded products, which are parts of instruments, to other firms, then the combined code letters form the manufacturers of the moulds, together with the contractor for the instruments will be shown as follows:- 

e.g.             S               Siemens brothers (for instrument)
                MPL           Moulded Products Ltd (for moulded product)

In the above example the upper letters indicate the item manufacturer, the lower letters the moulding subcontractor, followed sometimes by a number which represented the type of moulding material.


Made for WB by WB and BA is the material Made by PX for PX and the material code is '1'
Made by Ericsson for Ericsson and the material is '1' Made by Ericsson for TMC and the material is '4'
Not sure about the M and CL

Colours allotted to Manufacturers

Within cords and cables there are coloured cotton threads which identify the manufacturer.  These colours are to the British Standard for the Commonwealth and coloured threads are always listed in alphabetical order (British Standards PD 2379 - 1956).

Firm Colour Firm Colour
Automatic Electric CO., Ltd. Yellow. Macintosh Cable Co. Ltd. Red, Yellow.

British Insulated Cables. Ltd.

Black, Brown, Green.

Phoenix Electrical Co. Ltd.  


Erewash Electric Wire Co. Brown, Green, White. Reliance Electrical Wire Co., Ltd. Green, Red, Yellow.
Ericsson's Telephones. Ltd. Slate or Slate, White. Siemens Bros. & Co., Ltd. Blue, White.

General Electric Co. Ltd. (incorporating Peel-Conner Co.) 

Brown, Yellow.

Standard Telephones & Cables. Ltd.


International Electric Co. Ltd.

Blue, Slate.

Sterling Cable Co. Ltd

Blue, Green, Yellow.

London Electric Wire Co. & Smiths, Ltd.

Black, Red,.

Ward & Goldstone

Blue, Green.

L.P.S. Electrical Co.. Ltd. Blue, Green, White. Yorkshire Cable Co. Blue, Brown.


Title Codes

All BPO equipment, large and small, carried a 'title number'.

Telephones, 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 a Mark 1, the first modification as Mark 2 and the second as Mark 3 (and so on).  Up to around 1940 modifications were identified by three digits, starting with 234, for the original design (Mark 1), then 235 for the first modification (Mark 2), 236 for the second modification and so on.  Nobody can explain why 234 was the first iteration and when the changeover from the early "23X" markings to the later "Mark X" style occurred.

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 thus:-

 C34    No. 162


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Last revised: November 20, 2022