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
The sunlit uplands
On Saturday 31 May something historic happened. The Heads of the Valleys Road was finally complete.
Grand openings
Our much-loved Opening Booklets section has two new publications for you to explore, and we’re making some overdue changes to make them easier to find and easier to read.
Silver bullet
The Silvertown Tunnel is finally open for business. One question remains: what’s it for?
Have you seen...
The Heads of the Valleys
The A465 Heads of the Valleys Road is one of the most spectacular trunk roads in the UK, and building it required some of the most remarkable civil engineering. This is the story of how the road was built in the 1960s, and how it's being rebuilt today.
About this page
Published
Last updated
Published
Last updated
