Road Numbers?

In the spirit of Murphy, Sod and everybody else who had a law named after them, the Trafficmaster unit bleeped its message of impending gridlock as the last opportunity to leave the motorway passed. So there I was, stuck in a queue of traffic that occasionally lurched forward another few yards.

In these situations my defence against rising blood pressure is to go into a semi-yogic trance and let the brain wander. Which is how, prompted by having read a motorway sign about 15 times, I came to be contemplating the logic behind the UK's system of road numbering. Alright, I know this is hardly deep philosophical stuff, but it's about as deep and philosophical as you'll get from me.

So is there any logic to the system? Well, the answer is apparently yes. However, the responsibility for classifying roads rests with the labyrinthine Department of Environment, Transport and the Regions and generations of civil servants have developed the system over more than 70 years, so the logic is rather tortuous to follow at times.

Originally, there were no road numbers and navigating around Britain was a difficult task for pioneering motorists. It was the Automobile Association who first set about introducing a system of sign-posting to help their members. That was back in 1906 but the main routes were not numbered. The AA chose the old Roman names such as Ermine Street and Watling Street while other labels such as the Great North Road, Dover Road and Bath Road were selected simply because they described where roads went from London.

It was during the First World War that the military authorities first devised a system of road numbering. Not that this helped the ordinary motorist because the system remained a well-kept military secret until 1922 when the new Ministry of Transport published the first classified list of A and B class roads.

This national classification was based on six sectors radiating from the centre of London. Starting with the Great North Road as A1, the most significant radial routes were then numbered clockwise as A2, A3, A4, A5 and A6. Roads considered to be the next most important roads in each of the sectors were then labelled with two digit numbers such as A20, A21, etc through to A29. Less important roads were given three or four digit numbers such as A272 and A259.

Without wishing to offend the sensibilities of our Celtic cousins from the other side of Offa's Dyke, it explains why Wales is dominated by three and four digit road numbers starting with the number 4. And what about Scotland? Well, if you look at a road map, you'll find that north of the border they were given 7, 8, and 9 to play with.

So far so good but what was the reasoning behind calling London's orbital motorway the M25? There is still a logical explanation although, as with many new additions and extensions to the motorway network, the original logic has had to be adapted over the years. Parts of the London Orbital Motorway were planned or begun as separate relief roads around London all with a different classification. There was, for example, the M16 Outer Orbital to the north of the capital. Only the part relieving the A25 through parts of Kent and Surrey was known as the M25 during the planning stage.

It was not until Autumn 1975 when the first section opened between South Mimms and Potters Bar that the Minister of the day announced that, to avoid confusion, the entire motorway ring around London would be called the M25. A similar approach has been taken where other roads have been supplemented by new roads, e.g. M40 was chosen because it ran parallel to the A40 for much of its route.

Former major roads that cease to be part of the main road network after they are replaced or bypassed by new roads are often given new nondescript four digit numbers deliberately so as to discourage through traffic from using them.

The system of road classification has now developed to the extent that the Highways Agency issues fictitious numbers for film and television use. Where a drama series such as BBC 1's Casualty involves a serious road traffic accident, the road number used in the TV series is blacklisted from actual use for a period of five years.

But there is one motorway designation that will remain blacklisted for eternity. That is the M399. For those of you who didn't see the TV series or aren't familiar with Tom Sharpe's side-splittingly funny book "Blott on the Landscape", I suggest you read the book to find out why.