News that Transport for London – the body that controls the capital’s vast transport networks and main roads – has been looking at building an underground ring road has resulted in remarkably little adverse comment.

Although very much at the study stage, the ambitious plan would be for a 22-mile long underground tunnel encircling the centre of the capital.

The tunnel would work as a subterranean ring road and could, say supporters, release large amounts of surface space for new buildings, open spaces and cycle lanes because much of London’s cross-town commercial traffic will have been pushed underground.

Press reports claimed that the scheme could cost as much as £30bn. But Transport for London says that congestion in central London could, by 2031, rise by 60 per cent on today’s levels.

Much of that is expected to be commercial traffic, which will be servicing a city that is expected to see a huge rise in population, as it sucks in money and people from overseas. Removing traffic from the most polluted road corridors, which has to be a priority, now that pollution – as opposed to CO2 emissions – has finally risen to the top of the political agenda.