London to Bristol down the M4, and off at junction 19

From junction 12 westwards the M4 is one of the more agreeable motorways in the country, running across the Berkshire and Wiltshire downs with two service areas and very few surprises.

Everything difficult about this journey happens between London and Reading, where the motorway carries Heathrow traffic, Slough traffic, Reading traffic and everything heading to Wales all at once. Leaving before seven or after ten makes a difference of forty minutes.

Bristol sits across a gorge with Clifton on high ground to the west, the harbourside at the bottom and the university quarter climbing away from it. Distances that look short on a map involve substantial gradients and a one-way system that follows the contours rather than a grid.

The practical result is that a drop at the wrong end of a street can mean a steep walk. We ask for the address rather than the area, and the difference between Clifton Village and the Triangle is worth ten minutes and a hill.

Bristol operates a charging zone covering the central area, aimed at older vehicles. Like every such scheme it has been adjusted since it started, so we check what applies rather than working from memory.

Whatever is payable appears in the written quotation before you travel. It is a small sum in the context of a long journey and it is the sort of thing that should never appear as a surprise afterwards.

Junction 18 of the M4 serves Bath and junction 19 serves Bristol, and the two cities are twelve miles apart. A great many journeys we make in this direction take in both, either on the same day or across two.

For a passenger with meetings in Bristol and an evening in Bath, the car makes that trivial. By train it involves a change of city, a change of station and a timetable that does not much care about your schedule.

The airport sits eight miles south-west of the city at Lulsgate, on high ground reached by the A38 through Bedminster. There is no motorway to it and no railway, and the road is a single carriageway for much of the way.

From central Bristol it is thirty to forty minutes rather than the fifteen the distance suggests, and considerably longer at the peaks. It is one of the airports where a car genuinely is the practical option rather than the comfortable one.