A Short History of UK Car Registrations

Origins & Allocation of Marks

On 1st January, 1904, the UK government introduced a law (The Motor Car Act 1903) which stipulated that all motorised vehicles should be identified by distinguishing marks, now known as registration numbers, so that they may be easily traced in the event of accidents or contravention of laws The original law specified that each identifying mark would have a maximum of six characters and would have either a single letter or two letters to indicate the local authority that registered the vehicle, followed by up to five numbers, e.g. [AB 1234].

The allocation of index marks to English & Welsh County Councils & County Borough Councils was single letters from A to Y, and double letters AA to FP (with some gaps e.g. for Scotland and Ireland - see below). These were arranged in order of population figures from the 1901 census from London with letter A to Rutland with FP.

At an early stage it was decided that I and Z were to be allocated to Ireland and G, S and V were to be allocated to Scotland's authorities - though many G and V combinations were diverted elsewhere as it became clear that Scotland would not require all of these marks. Unlike England & Wales, the allocations to Ireland & Scotland were made in alphabetical order of counties, followed by boroughs, with a few exceptions.

Blackpool and Tynemouth; awarded CBC status later in 1904 took the next available marks FR and FT. Then, as each authority reached the end of its allotted mark, it was allocated another. London was quickly awarded LC, LN, LB, etc. In this way, the areas with larger populations received more marks as required, whilst the smallest areas only received one mark.

In 1932 the first three letter combination appeared ARF for Staffordshire. The first letter was a serial, which preceded the existing two letter mark. Many councils issued marks in the order of their original issue; Bedfordshire for example issued ABM, ANM, ATM, AMJ, then BBM etc.


Scotland was ostensibly allocated all index marks containing the letters 'G', 'S' or 'V', and the single-letter codes were allocated to Glasgow, Edinburgh and Lanarkshire respectively. The each county was allocated one mark each in alphabetical order with codes beginning with 'S', so 'SA' for Aberdeenshire, 'SB' for Argyllshire, 'SD' for Ayrshire, 'SE' for Banffshire and so on. There were some "out of sequence" oddities, e.g. 'SC', 'SF' and 'SG' were allocated to Edinburgh.

Once these had been allocated as far as 'SY' (Midlothian), the sequence continued from 'AS' (Nairnshire), 'BS' (Orkney) through to 'PS' (Zetland, or Shetland). ('SZ' was allocated to County Down in Northern Ireland - see below). The remaining 'S' codes were allocated to burgh councils with Aberdeen receiving 'RS', Dundee 'TS', Glasgow 'US' and so on. Any remaining requirements were met out of the 'G' and 'V' sequences, but these were not all used by Scottish authorities. For example 'GA', 'GB', 'GD', 'GE' and 'GG' went to Glasgow, 'GM' to Motherwell and Wishaw, 'AG' to Ayrshire, 'FG' to Fife, 'RG' to Aberdeen and 'WG' to Stirlingshire, whilst 'VA' and 'VD' went to Lanarkshire and 'AV' to Aberdeenshire. The remaining codes in these sequences were allocated to authorities in England and Wales. The only mark outside of the 'G', 'S' and 'V' marks issued to a Scottish authority was 'YJ', which was allocated to Dundee in 1932.


In Ireland the 'I' series was initally allocated to the counties in alphabetical order, beginning with 'IA' for Antrim, 'IB' for Armagh, 'IC' to Carlow, 'ID' to Cavan and so on (at that time all of Ireland was still part of the UK). As with the Scottish system, cities were allocated marks from 'OI' (Belfast) to 'YI' (Dublin).

In the late 1920s marks with the letter 'Z' were introduced. As this was following partition in 1922, the marks were split, with those beginning with 'Z', i.e. 'ZA', ZB', 'ZC' etc going to the Republic and those ending with 'Z', i.e. 'AZ', 'BZ', 'CZ' etc going to Northern Ireland.

In contrast to the rest of the UK, after Northern Ireland had issued two letter marks in the order they were allocated, followed by "reversed" two letter marks, the three letter combinations were issued with up to 4-digit numbers - e.g. [ABZ 1234] - instead of 3. This is the system still being used at the time of writing.

The Republic of Ireland continued working within the British system after 1922 issuing new marks as required. The last marks were issued under this system in 1986 before a completely new year-number based system was introduced. The issue of marks was usually two letter, three letter, the "reversed" two letter, and "reversed" three letter systems - the year-letter suffix/prefix system was never used.

Three-letter marks

By the 1930s, despite the larger authorities being allocated a larger number of index marks, the available codes were running out, so the system was extended to replace one number in the two-letter system with a letter. This extra letter was added before the index mark, however, so for example Reading, which had two index marks, [DP] and [RD], issued [ADP 1] to [ADP 999] in 1937-1938, then [ARD 1] to [ARD 999] in 1938. Then in 1939 the sequence continued with [BDP 1] to [BDP 999], followed by [BRD 1] to [BRD 999] and so on.

Reversed Registrations

By the 1950s, many authorities had already exhausted the [ABC 123] combinations and needed new system to distinguish newly registered vehicles form old ones. The solution was to reverse the sequence from letters followed by mumbers to numbers followed by letters. The same system was used as before, i.e. initially single-letter and double-letter marks were used with numbers up to 9999, followed by three-letter marks in the following formats: [1234 A], [1234 AB], [123 ABC].

Annual suffix letter

As these marks were also fast running out, a new system was needed to extend the issue of registrations into the future. Thus a "suffix" letter denoting the year of registration was added to numbers in the format [ABC 123A]. The suffix letter system was phased in from 1963-5, because authorities had used up their allocations at vastly different rates, e.g. Somerset County Council had reached the "reversed" YYC mark, while SJ (Buteshire CC in Scotland) had only reached SJ 2860! So, while the larger authorities generally started at 'A', most remaining authorities didn't issue suffixed registrations until 1964 with the 'B' suffix. Finally, the remaining few, smallest areas were brought into the new system with the 'C' suffix in 1965.

In the first five years the suffix letters were issued from January to December, with 'A', 'B', 'C' and 'D' representing 1963, 1964, 1965 and 1966 respectively. However, this produced too much demand at the start of the year and, following pressure from the motor industry, the new suffix for each year was introduced in August instead of January. Hence, 'E' was issued from January 1967 as normal, but 'F' was then brought in from August the same year. This system was used until 1983, with only the letters 'I', 'O', 'Q', 'U' and 'Z' being excluded to prevent ambiguity. In August 1983, after the 'Y' suffix year, the system was again reversed, with the year letter as a prefix rather than a suffix, e.g. [A123 ABC].

In 1999, a six-monthly period was introduced, with two letters being used each year beginning in March and September to try to even out demand over the year. The 'T' prefix was issued from March 1999, 'V' in September 1999, 'W' in March 2000, 'X' in September 2000 and, finally, 'Y' in March 2001. From September 2001 an entirely new system was introduced.

New Registration System

The new registration system introduced in September 2001 was in the format [AB12 CDE]. The first two letters were a location indicator, with the first letter denoting a region and the second letter allocated to an issuing office within each region. For example, Scotland has the 'S' prefix, and the allocation of offices within Scotland are 'SA' to 'SJ' to Glasgow, 'SK' to 'SO' to Edinburgh, 'SP' to 'ST' to Dundee, 'SU' to 'SW' to Aberdeen and 'SX' and 'SY' to Inverness.

The next two numbers indicate when the vehicle was registered. For the March issue each year, the last two digits of the year are used, so '02' for March to August 2002, '03' for March to August 2003 and so on. The September issue is the last two digits of the year, plus 50, so September 2001 to February 2002 is '51', September 2002 to March 2003 is '52' and so on. At the time of writing (December 2017), the year indicator is '67'. (Note that the year code '01' was not used as the new system began in September 2001 with the '51' code.

The final three letters are issued randomly and, as the letter 'Z' can now be used in this portion of the registration number for the first time, this gives a possible total of 13,824 registrations for each combination of the location and year indicators, minus a few 'unacceptable' combinations such as 'ARS', 'FUK' etc. This system will last for 50 years until the issue of the '99' indicator in September 2049.


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