Most Britons love new roads, in theory. Which is why British governments love announcing them, as the coalition has this week. Actual roadbuilding, however, is almost always expensive, slow and intensely controversial. Even if the Conservatives are re-elected next May, the great schemes of the past suggest their plans to spend £15bn on 84 projects all over England are far from guaranteed.

London ringways

It seems incredible now, but as recently as the late 1960s it was still the plan to build a series of concentric circular motorways not just around London, but in it. The eastern side of the inner ring, ring 1, was built and lives on as the section of the A12 that runs south from Hackney and crosses the river through the Blackwall tunnel. The rest was mostly too unpopular – and then, in the 70s, too expensive – to persist with.

M1 London extension

Originally – and unbelievably – the M1 was supposed to smash through west London all the way to Marble Arch. En route, it was also supposed to join up with the new ringways, one of which would meet it at Stirling Corner, so construction of the junction began. With no road to join to, however, its roundabout had to be transformed into the rather awkward Scratchwood services, now known as London Gateway, which is why (in case you have ever wondered) the M1 has no junction 3.

Belfast Urban Motorway

In 1964, Belfast was supposed to get something similar to London. The Belfast Urban Motorway, as it was known, would create a large ring of free-flowing traffic on a network of concrete flyovers over the city. Mounting opposition led to a public inquiry, which ruled in 1973 that only the first phase would be built, joining the M1 to the M2. Even trying to build this proved impossible during the Troubles, however, so the plan was reduced to a dual-carriageway, known today as the Westlink.

Roads for Prosperity

After decades of underinvestment, this white paper published by Margaret Thatcher’s government in 1989 heralded “the largest road building programme for the UK since the Romans” . The words were a clue to the muscle that would have been needed to make it happen. Among the proposals were widening the A140 in East Anglia, building a bypass at Newbury, and even finally building that forgotten road at Scratchwood services. However, the scale of opposition was among the largest since Boudicca. Twyford Down and Newbury, especially, became the scene of celebrated protests that were unsuccessful in themselves, but which slowed momentum to the point where many other schemes were quietly reviewed out of existence.