Route
Junction number
8
Markerpost
30.8 km
Name
Merstham Interchange
Type
Terminus
Not a terminus
Other routes
M25
Authority
Restricted turns
Full access
Services
No services
M23 J8 Merstham Interchange
Layout and signage
(M4 
Lane configuration
- Lane 1 exits and does not return.
- Lane 2 exits and returns after the junction.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 1 exits and returns after the junction.
- Lane 2 exits and returns after the junction.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
Other events
National Speed Limit begins
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...
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Published
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