Number plates were not around when motor vehicles first had to be registered to drive on the roads back in 1896 when the Government introduced the Highway Act as more and more vehicles started to appear on the roads. The act didn't require drivers to display any registration number but it did require drivers to register their vehicles with their local council. The act, interestingly, introduced more than the idea of vehicles having to registered but it also made it compulsory for vehicles to have lights, increased the speed limit, and formalized the convention of us driving on the left-hand side of UK roads.
At the beginning of the 20th century with more motor vehicles driving on the roads and accidents occurring more frequently, it became increasingly necessary for there to be a means to identify vehicles. This then prompted the introduction of The Motor Car Act 1903 which made it compulsory for every registered car to have a number plate. However the idea of number plates was first introduced 5 years prior to the world when it was first implemented in the Netherlands by the Dutch authorities.
The first number plate that was issued in the UK was A1 and was registered to a man called Earl Russell who queued outside the London Council offices all night in hopes of getting the first plate. It also marked the start of the idea of having a distinctive, personalized or cherished plate for vehicles.
Since the introduction of number plates the registration system had to change 4 times to accommodate the every-growing demand for vehicle registration.
The first plates were dateless and had no way of telling what year they were issued, however the letter or pair of Letters at the start of the plate represented where the vehicle was registered. But with the increasing amount of vehicles requiring registration, it became obvious that the numbering system wasn't going to have enough combinations to meet demand and the need for a new system to be introduced.
This led to the introduction of the Suffix system in 1963 which added a letter at the end of the plate which indicated the year of registration. However the administration of the task of issuing plates had turned into a massive task over the years as everything was done manually and locally, there were also delays with registrations. Police checks on vehicle records were time consuming and labour intensive. There needed to be a revamp of the system with the use of modern technology, thus resulting in the creation of the DVLA system in 1974 which took over the responsibility of vehicle registration from local councils.
A new system for number plate registration was introduced in 1983, known as the Prefix system. The Prefix system saw the letter indicating the year of registration moved to the beginning of the number plate, followed by random numbers, and the area code letters. this system continued until August 2001.
This leads to the modern registration that we all know today. This features 2 letters that represent the area code, numbers that represent the age it was registered, and 3 random letter combination. This system was created based on police evidence which suggested witnesses are more likely to remember the letters of registration far more easily than the numbers which made sense as people read from left to right, and so that is why the area code was moved to the beginning of the registration.