Road scheme and chronology data is courtesy SABRE (where much of it was gathered by member Ross Spur), with additional data from the UK Motorway Archive, the Scottish Roads Archive and the Northern Ireland Roads Site.
What might it have been like to stand in one spot and witness the arrival, and the uncertainty, of plans for an urban motorway in West London?
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.
The second part of the story, where we learn why exactly the M4 gets narrower on the final approach to Europe’s biggest city.
An early triumph of the motorway programme, the M4 between Chiswick and Langley linked Central London to Heathrow - then still known as London Airport - and was the start of a new motorway west.
