Sitting in a lay-by beside the A38, to avoid the extortionate car parking charges at Bristol Airport, the traffic speeds past. In the dying evening light, cars appear as headlights and disappear as tail lights. Sometimes there is a lull and the ordinary two-lane road is just another country route. It is hard to believe that this road was once the main road from the West Country to the Midlands.

In the old AA handbooks and on the road maps that could be bought at petrol stations such roads would have numbers like A38 (T). The legend at the foot of the map said that the “T” indicated “trunk road.”

To this day, I could not give a definition of a trunk road. I would have supposed that it meant long distance – like a trunk call that people made with their telephone, when it was absolutely necessary. Although the long distance call was more obviously a long distance than a long distance road was. When you were making a long distance call, you were in one place and the other person was in a far off place and there was nothing in between, whereas the A38 passes through countless towns and villages and varies in nature from motorway-like to by-road, and from busy high street to quiet byway.

The A38 was not so much a trunk road as an amalgam of roads joined by a common number. The BBC once broadcast a documentary describing the A303 on its journey westwards; the tale of the A38 would be far more complex and would cover many episodes. According to the HIghways England map, most of the length of the A38 is de-trunked, including the section that passes a lay-by five miles from Bristol Airport. Only the expressway that carries traffic from Exeter to Plymouth and into Cornwall still retains the exalted status of the old A38.

To have travelled the A38 by car in the first days of its T-status would have been an experience very different from driving the route today. Cars would have been few and journey times would have been long. There would have been no by-passes; in the country, agricultural vehicles would have been frequent; in the towns, streets would frequently have been at a standstill. And yet there would have been excitement in that independent travel, no timetables by which to abide, no sooty carriage doors or windows to dirty the clothes of unwitting passengers; just the letter “T” to reassure you that you had far to travel on a road of significance.