Since 1996, three sections of a new A421 expressway have been built, progressively completing a fast route that serves to link Cambridge to Milton Keynes and Bedford to the wider world.
It was the UK's only single-carriageway motorway, and twenty years ago it ceased to exist. This is the story of the strange fascination it held, and of my place in history.
It makes the traffic situation in one part of West London much more bearable but it should have been removed more than quarter of a century ago. It's amazing what you can do with a big Meccano kit.