M25 J12 Thorpe Interchange

Layout and signage

Basingstoke
Southampton
Richmond
M3 Link
  M3     M3   Basingstoke
Southampton
Richmond
M3 Link

Lane configuration

LanesLanesLanesLanesLanesLanesLanes

  • Lane 1 exits and does not return.
  • Lane 2 exits and returns after the junction.
  • Lane 3 continues ahead.
  • Lane 4 continues ahead.
  • Lane 5 continues ahead.

LanesLanesLanesLanesLanesLanesLanes

  • Lane 1 is gained from the entry sliproad.
  • Lane 2 exits and returns after the junction.
  • Lane 3 continues ahead.
  • Lane 4 continues ahead.
  • Lane 5 continues ahead.

Other events

  • Signs Variable Speed Limits apply
  • Signs Variable Speed Limits apply

In this section

What's new

The road that made no sense

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 forever bottleneck, part 2

The second part of the story, where we learn why exactly the M4 gets narrower on the final approach to Europe’s biggest city.

The forever bottleneck, part 1

The M4 into London was one of the UK's earliest and most ambitious motorway projects. It was bold, pioneering... and almost instantly regretted.

Share this page

Have you seen...

North Cross Route

The route and the history of the North Cross Route, proposed in the 1960s as the northern side of London's innermost motorway ring road.

About this page

Published

Last updated