In 1903, with increasing vehicles on the road in the UK, the Motor Car Act made it mandatory to display registration plates beginning from January 1904.
In the UK, London, the largest authority, was allocated registration numbers with the letter "A", Lancashire was given "B", and so on. The letters G, S and V were reserved for use in Scotland. Northern Ireland also had specific letters allocated for their registration numbers, namely I and Z. Since there are more than two authorities in NI, these letters were used in alphabetical order, for example IA was given to County Antrim.
Obviously, this system was finite so, as more vehicle plates were registered, it had to be expanded - and in 1905, London was given LC since it had used up its original single letter allocations.
By 1932, a third letter had to be introduced almost everywhere. This could be followed by 1, 2 or 3 numbers. This system left the freedom to reverse letters and numbers if necessary - so, for example, UXL 921 could be re-issued as 921 UXL. This helped to cater for the increase in vehicle ownership after the war.
In 1963, a year identifying letter (known as a suffix letter) had to be introduced - again, as a response to increasing numbers of vehicles on the road. For example, on a personalied plate like ADC 113B the B would come to indicate the year of manufacture of the vehicle, in this case 1964.
In 1974, the manual system of issuing registration numbers by local authorities was replaced by a new centralised computer system based at Swansea. The original name for this concrete sprawl of buildings was DVLC (Driver and Vehicle Licensing Centre). At the same time, a network of local Department of Transport Offices were formed.
As we all know, the alphabet only has 26 letters. NI kept 'I' and 'Z' for its sole use, also 'Q' is always used on registration numbers to designate a vehicle where the year of manufacture is unknown.
'O' was never used since it could be confused with the number zero and 'U' was never used since it resembled 'V' on a plate.
With a new letter being used every year, this meant that by 1983, the suffix system of letters had reached its end. It was agreed that registration numbers should now take the form of a prefix year letter, followed by 1, 2 or 3 numbers plus 3 area identifying letters.
So a vehicle displaying an 'A' prefix would have been manufactured between August 1983 to July 1984, and this format of registration plate ran up to the 'Y' prefix - indicating a year of manufacture between March 2001 and August 2001.
You'll note that the prefix range was used up faster than the suffix - this was because in 1998 ('S' prefix) it was decided to change from issuing a single letter per year to two - to accommodate the number of vehicles being registered, but hastening the speed at which the DVLA would run out of letters.
With the prefix format it was decided that there was no fair way to allocate the numbers 1 through 20 so these were withheld. From the 'J' prefix onwards, even more registration plates were withheld, for example "rounded" numbers like 30, 40, 50 etc. or numbers with matching digits like 22, 33, 44... 111, 222, 333 etc.
This stockpile of reserved plates made the popular "Make Your Own Plate" range possible - thus allowing many more people to participate in the personal registrations market.
After reaching the letter Y, and after extensive consultation, it was decided to introduce the "New Style" registration numbers. These came into being on Sept.1st 2001 and took some getting used to for number plate dealers as well as the general public. Briefly, there are two letters at the front which represent the area identifier followed by two numbers (indicating the year of release) followed by 3 random letters.
NV = NORTH (Newcastle or Stockton local offices) where N = North and 2nd letter has to be from the range A to O or P to Y.
53 = issued half-way through 2003 (Sept - Feb).
ZPB = 3 randomly allocated letters.
WJ = WEST (Exeter, Truro, Bristol).
06 = Issued March to Aug 2006.
XVZ = Random letters.
The new style numbers offered new ways to form good matches to names and words - JO56 HUA, PE54 NUT, SP07 RTY, JA53 ONN and so on. And the extra letters mean that there are some 8 million combinations available for each release. You can see about crafting your own selection from this format on the Make Your Own Plate pages.