M25 Junction 21: the M1
Junction 21 is where the M25 meets the M1, near Bricket Wood in Hertfordshire. It links motorway to motorway; for local roads, Junction 21A is just to the east, where the A405 crosses for St Albans and Watford.
Live traffic speed flow: M25 Junctions 20 to 22
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Where the roads go
Take the M1 north for Luton, Milton Keynes and the North, or south for Watford and London. On the M25, the next junction anticlockwise is Junction 20 for Kings Langley, and clockwise it is Junction 21A, followed by Junction 22 for the A1081 and London Colney.
Junction 21A
Junction 21A is only a short distance east of Junction 21, and link roads run alongside the M25 between the two, so traffic for the M1 and for St Albans changes lanes in a short space. The map shows both junctions. Allow for queues on the slip roads at busy times.
For news about the M1 itself, see our sister site M1 Traffic.
M25 Junction 21 at a glance
| Junction | M25 Junction 21 |
| Meets | the M1 (M1 Junction 6A) |
| Near | Bricket Wood, Abbots Langley and St Albans |
| Next junction clockwise | J21A (A405, St Albans) |
| Next junction anticlockwise | J20 (A41, Kings Langley) |
| Traffic news for the M1 | M1 Traffic |
Live traffic news at M25 Junction 21
Live traffic news at M25 Junction 21
Incidents and roadworks between Junction 20 and Junction 22 that we are aware of.
M25 Anti-clockwise Jct 20 entry slip lane 1 closure
02:543 Oct 2026reported 12 min ago
- Location
- M25 J20 anti-clockwise access
- Direction
- Anticlockwise
- Lanes closed
- Slip road closed
- Reason
- Roadworks
- Schedule
- 23:00 Sat 3 Oct 2026 → 05:30 Sat 3 Oct 2026
This is the news for Junction 21 only, not the whole M25. For the rest of the motorway see all the latest M25 traffic news, the overhead signs and the speed limits in force now.
Updated 03:07 Sat 3 Oct 2026