Of course, in the other direction, the names are different. You'll still find these names in use, especially where 20th century development has created ribbons of housing along them.
Names are useful for postal addresses.
But as the internal combustion engine replaced the horse and cart in the period after the Great War, and it became possible to travel further than the next town in a day, it became clear that the bureaucrats would have to step in. Plans would have to be made, rules would have to be invented, signs would have to be erected. Clockwise, of course. In the sectors defined by these spokes, the major roads were given two-digit numbers. Some of these roads also radiated from London, and were numbered clockwise, but others were just fitted in to the system as convenient.