Manufacturer's factory identification codes
These show where the pumping process was completed.
Code Manufacturer
A Mullard, Blackburn, prior to Jan 1951
A Thorn, Tottenham, prior to April 1964
AB Sylvania-Thorn, Enfield
AC Thorn-AEI, Footscray
AD Thorn-AEI (Brimar), Rochester
B Edison Swan, Baldock, prior to Sept 1945
BA AEI, Woolwich
BC Joseph Lucas, Birmingham
C Edison Swan, Ponders End, prior to Sept 1951
CC Cathodeon, Cambridge
CE 20th Century Electronics, prior to March 1957
CF 20th Century Electronics, New Addington
CN Pye Industrial Electronics
CO Newmarket transistors, Newmarket
CS Cathodeon, Southend
D Mullard Radio Valve Co., Mitcham
DA Mullard Radio Valve Co., Blackburn
DB Mullard Radio Valve Co., Salford
DC Mullard Radio Valve Co., Whyteleafe
DE Mullard Radio Valve Co., Fleetwood
DF Mullard Radio Valve Co., Waddon
DG Associated Semiconductor Manufacturers, Southampton
DH Societe Anonyme Philips, Brive, France
E Thorn-AEI, Brimsdown
EA Edison Swan, Ponders End
EB Edison Swan, Gateshead
EC Edison Swan, Tottenham
EN Thorn-AEI, Sunderland
F STC, Paignton
FB STC, Footscray
FC STC, Lorenz,. Esslingen, Germany
FD STC, Rochester
FDA Alexandria, NSW, Australia
FE STC, Oldway (Additional to Paignton factory 'F')
FF STC, Harlow
G Ericsson, Beeston
GA (Ericsson), AB Svenska Elektronror, Stockholm, Sweden
H Hivac, Harrow
HC Hivac, Chesham
HR Hivac, Ruislip
J STC, Crewkerne, prior to Jan 1946
J Radar Electronic Equipment
JA SGS Fairchild, Ruislip
JB SGS Fairchild, Agrate, Milan, Italy
JD Elliott Bros. (London) Ltd, Borehamwood
JE Elliott-Litton, Borehamwood
JK La Radio Technique, Suresne, Paris, France
JN International Rectifier Co., (GB) Ltd, Oxted
JQ Associated transistors, Ruislip
JT Microwave Associates Ltd, Luton
K Electronic Tubes, High Wycombe
L CSF, Levallois-Perret (Seine), Paris, France
L MOV prior to Oct 1951
LB CSF, St. Egreve, Grenoble, Isere, France
M Gramophone Co., Hayes
MA EMI research labs, Hayes
MB EMI research labs, Ruislip
ME EMI, Hayes
MR EMI (Valve Division), Ruislip
MT EMI, Treorchy
N Nore Electric, Southend
N STC, Footscray, prior to August 1951
NP Texas Instruments, Dallas Road, Bedford
NQ Texas Instuments, Bedford
NR Texas Instruments, Nice, France
O Rank Cintel, Lower Sydenham
OR Rank Cintel, Rotunda
OS Rank Cintel, Sidcup
P Philips, Eindhoven, Holland
P GEC, Shaw, prior to August 1948
PA Philips Teleindustri, Stockholm, Sweden
PDA Philips, Hendon, Australia
Q English Electric Valve Co., Chelmsford
QB Marconi Wireless Telegraphy Co., Great Baddow
QC Marconi Wireless Telegraphy Co., Chelmsford
QD English Electric Valve Co., Stafford
QE English Electric Valve Co., Kidsgrove
QF English Electric Valve Co., Nelson Research Labs, Hixon
R Ferranti, Moston
R Ferranti, Gem Mill, prior to July 1947
RA Ferranti, Edinburgh
RB Ferranti, Dundee
RC Ferranti, Chadderton, Oldham
S AEI, Rugby
SA AEI, Lutterworth
SB AEI, Lincoln
SC CFTH, Usine de Joinville, Seine, france
SD SESCO, Rue de L'Amiral, Mouchez, Paris, France
SDA Amalgamated Wireless, Australia
SF CFTH, Rue Mario-Nikis, Paris, France
SL AEI, Leicester
SP AEI, Peterborough
T British Tungsram, Tottenham
U MOV, Bulmer, prior to Oct 1945
U Nucleonic and Radiological, Stratford
V Cossor, Highbury, prior to Sept 1945
V Gilbert Photoelectrics
VA Westinghouse, Chippenham
VF MCP Electronics, Alperton
VL Hughes Internations (UK) Ltd., Glenrothes
VR Brucsh Crystal Co., Hythe
W GEC, Hirst Labs, Wembley
ASM Ltd
WB GEC, Coventry
WD Claude General Neon Lights, Wembley
WE ASM Ltd, Hazel Grove
WF ASM Ltd, Broadstone
X MOV, Springvale, prior to Oct 1951
Y MOV, Moray, prior to April 1945
YA Leigh Electronics, Havant
YC Semiconductors Ltd., Cheney Manor, Swindon
YD Semiconductors Ltd., Towcester
Z MO Valve Company, Hammersmith
ZA MOV, Gateshead, prior to March 1957
ZB MOV, Perivale
ZC MOV, Springvale, prior to August 1957
ZD MOV, Dover, prior to Dec 1956
ZE Osram GEC Lamp Works, MXT Dept, prior to March 1957
