The Observer Magazine of 17 October 1971 wondered ‘How Many Cars Can Britain Take?’ given the 15.5m on the road then. Philip Llewellin wrote: ‘If the professional crystal gazers are proved right… there will be 34.2m vehicles – including 29.1m cars – on our roads by the year 2000.’ It turned out to be 27.2m cars in 2000, but more than enough to justify his assertion that ‘jam today has become part of our way of life’.

The situation called for some vivid comparisons of the problem: ‘Enough to create a nose-to-tail jam about 97,000 miles long. Enough to clog solid a 110-lane motorway from Land’s End to John o’Groats. Enough to girdle the equator four times.’

The solution then – and for a long time after – seemed to be to build more roads. The director of the AA wasn’t worried by the thought of more than 34m vehicles on the roads as long as there was ‘progress in Britain’s road programme’ and backed the British Road Federation’s calls for 3,000 miles of motorway by 1980.

Llewellin wrote about a pioneering experiment in the Peak District National Park where visitors to the ‘beautiful Goyt Valley pay 20p to park and are then transported, free of charge, by mini-buses’. He noted that though such a scheme might have been expected to arouse enormous opposition from the ‘I’ve paid my road tax’ angry brigade, it had been well-received.

What of other solutions? There was a nod towards alternative forms of private transport becoming available by 2000 – ‘family helicopters’, ‘moving pavements’ and ‘dial-a-destination taxi-type services to revolutionise transport’. Hmm, and where are those jet packs, too?

The only thing wrong with the brilliant cover of Britain so teeming with Ford Zodiacs that a few have been pushed off the edge is that the water level is likely to rise to meet the cars before they get a chance to crash into the sea.