Route
Junction number
21A
Markerpost
123.8 km
Name
Bricket Wood Interchange
Terminus
Not a terminus
Other routes
A405
Authority
Restricted turns
Full access
Services
No services
M25 J21A Bricket Wood Interchange
Layout and signage
Lane configuration
- Lane 1 exits and does not return.
- Lane 2 continues ahead.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 1 is gained from the entry sliproad.
- Lane 2 continues, with option to exit.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
Other events
Variable Speed Limits apply
- Variable Speed Limits apply
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.
Have you seen...
Low Emission Zone
A first step towards emissions-based road pricing, a pointless measure to enforce something that's happening anyway, or another leap forward in traffic planning from the people who created the Congestion Charge? It's hard to say.
About this page
Published
Last updated
Published
Last updated
