Route
Junction number
1A
Markerpost
32.5 km
Name
Denham Interchange
Terminus
Not a terminus
Other routes
M25
Authority
Restricted turns
Full access
Services
No services
M40 J1A Denham Interchange
Layout and signage
Lane configuration
- Lane 1 is gained from the entry sliproad.
- Lane 2 continues, with option to exit.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 1 exits and does not return.
- Lane 2 exits and does not return.
- Lane 3 splits to create a new lane.
- Lane 4 continues ahead.
What's new
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The M4 into London was one of the UK's earliest and most ambitious motorway projects. It was bold, pioneering... and almost instantly regretted.
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