UK REGISTRATION / TAG SYSTEM
The following courtesy of N. Hunter of the UK
Accuracy not guaranteed to be 100%
( this is a government we are dealing with here !! )
Submitted by BigMack@bigfoot.com

As follows, based on date of first registration, NOT build date:
AAA123A - Jan-Dec 1963 AAA123B - Jan-Dec 1964
AAA123C - Jan-Dec 1965 AAA123D - Jan-Dec 1966
AAA123E - Jan '67/July '67 AAA123F - Aug '67/July '68
AAA123G - Aug '68/July '69 AAA123H - Aug '69/July '70
AAA123J - Aug '70/July '71 AAA123K - Aug '71/July '72
AAA123L - Aug '72/July '73 AAA123M - Aug '73/July '74
AAA123N - Aug '74/July '75 AAA123P - Aug '75/July '76
AAA123R - Aug '76/July '77 AAA123S - Aug '77/July '78
AAA123T - Aug '78/July '79 AAA123V - Aug '79/July '80
AAA123W - Aug '80/July '81 AAA123X - Aug '81/July '82
AAA123Y - Aug '82/July '83 A123AAA - Aug '83/July '84
B123AAA - Aug '84/July '85 C123AAA - Aug '85/July '86
D123AAA - Aug '86/July '87 E123AAA - Aug '87/July '88
F123AAA - Aug '88/July '89 G123AAA - Aug '89/July '90
H123AAA - Aug '90/July '91 J123AAA - Aug '91/July '92
K123AAA - Aug '92/July '93 L123AAA - Aug '93/July '94
M123AAA - Aug '94/July '95 N123AAA - Aug '95/July '96
P123AAA - Aug '96/July '97 R123AAA - Aug '97/July '98
S123AAA - Aug '98/Feb'99 T123AAA - March '99/Aug '99
V123AAA - Sept '99/Feb '00 W123AAA - March '00/Aug '00
X123AAA - Sept '00/Feb '01 Y123AAA - March '01/Aug '01

From 1 September '01, there will be a new system, as follows:
The new registration marks will all be made up of seven characters.
There are three parts to the registration mark, each with a separate meaning.

The first two letters show where the vehicle was registered, the 'local memory tag'.

The two numbers indicate the age of the vehicle, the 'age identifier'.
The last three letters give a unique identity to a vehicle, the 'random letters'.
The following URL provides even more info (if you're not TOOO bored already...)
http://www.personallyyours.co.uk/info/default.htm