Greg Hennessy ) gurgled happily, sounding much like they
were saying :

You're implying that it needs only 3 characters to identify the
vehicle.

Where did I imply that. A vehicle is *uniquely* identified from the
26^3 combination of the 3 character remainder, not the 4 characters
wasted on a static year / registration office. Thats only ~17.5k odd
combinations which one must assume a busy registration office would
easily consume in a matter of days/weeks. Especially with bulk
registrations from fleet buyers.

Erm, not quite.

A vehicle is *uniquely* identified by the full seven characters.

For example - AB51DEF, AB02DEF and AB53DEF might all exist.
AB51DEF, GH51DEF, KL51DEF might all exist.

While it's possible that the 17,500 AB51 registrations may well only last
a week, the office that issues AB has a number of series available to it
for the six month period dictated by 51.

The smallest allocation of codes to an office are Inverness and Truro,
with two apiece, and Bangor and Aberdeen with three apiece.

There's one code allocated to new cars registered to addresses on the
Isle of Wight.

http://www.dvla.gov.uk/vehicles/regm...ent_system.htm
has a disclaimer, too - "Please Note: In the event of one office
receiving an exceptionally high demand that depletes its stock of
registration marks, marks may be transferred between DVLA local offices."

Since there's 19x23 regional identifiers, there's a total of 7.7million
unique registrations available in each six month period.

According to the SMMT, there was a "record" 2.6million new cars
registered in the whole of 2003. OK, that's cars, not
trucks/busses/bikes/whatever, but even so, it's a long way off the 15.4
million available plates....