You don't expect The Highway Code to carry political messages although, of course, it does. Herbert Morrison, Minister of Transport in 1931 and Lord Peter Mandelson’s grandfather, described the first in 1931 as: “A code of good manners to be observed by all courteous and considerate persons.” Leslie Hore-Belisha (he of the beacons) wrote in the foreword to the 1935 edition: “In every human activity there is a standard of conduct to which, in the common interest, we are expected to conform.” Yet the compilers could not avoid reflecting social distinctions. Not only is the 1935 driver obviously a professional gentleman, a banker or a doctor perhaps, but the coachman solemnly rotating his whip is conducting a carriage for nobility or gentry.

By the 1946 edition the socialists were in power, so perhaps in view of the shorter tenure expected of Ministers of Transport, no name is attached to the Foreword. The signalling driver is now obviously middle class. No more a racy 2-seater, his car is an upright saloon alongside a cloth-capped cyclist. The coach has been replaced by something working-class, looking suspiciously like a brewer’s dray.

The pictures come from Highway Code (Michael O’Mara Books, 2008), which very sensibly comments that stopping distances in the 2007 Highway Code were the same as those in the 1946 edition. Officialdom never really understood stopping distances. The late Jeff Daniels and I once did a feature in Autocar debunking police theories on estimating cars’ speeds from skid marks. Disc brakes, grippy tyres, decent servos and anti-lock mechanisms, not to mention other improvements in car behaviour have always been well beyond the reach of a bureaucratic mind.