Route
Junction number
21
Markerpost
122.8 km
Name
Chiswell Interchange
Type
Non-standard interchange
Terminus
Not a terminus
Other routes
M1
Authority
Restricted turns
Some turns restricted
Services
No services
M25 J21 Chiswell Interchange
Lane configuration
- Lane 1 is gained from the entry sliproad.
- Lane 2 continues ahead.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
- Lane 1 exits and does not return.
- Lane 2 continues ahead.
- Lane 3 continues ahead.
- Lane 4 continues ahead.
Other events
Variable Speed Limits apply
- Variable Speed Limits apply
What's new
A bridge under troubled bridges
A bridge that was ruined by another bridge, and a type of highway planning beyond any of the UK’s worst nightmares.
The monster seen from below
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?
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.
Have you seen...
The Improbable A39
It crosses cattle grids and untamed moorland, it climbs 1-in-4 hills and plummets through hairpin bends, it runs single-track through woodland and historic villages. It's rugged and beautiful. Is it really the A39?
About this page
Published
Last updated
Published
Last updated
