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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Go to our live M25 traffic speed flow map ›
NOTE: The speed flow, overhead sign messages or other information shown on our live traffic speed flow map is updated every few minutes. We cross check the data and aim to provide warnings if there could be a delay or an inaccurate speed reading. There can be occasions, beyond our control, and despite our best efforts where the speed flow could be inaccurate. We cannot therefore guarantee the speed you can expect on any stretch of the motorway is always accurately shown. However we hope you will find our live traffic speed flow map a useful tool in trying to plan your journey. Safe driving.
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.
M1 northbound Jct 6 to Jct 8 carriageway closure
02:58 (2:58am)14 Oct 2026reported 3 min ago
- Location
- link road from M25 J21 clockwise to M1 J6A northbound
- Direction
- Clockwise
- Lanes closed
- Carriageway closed
- Reason
- Roadworks
- Schedule
- 22:00 (10pm) Tue 13 Oct 2026 → 05:00 (5am) Wed 14 Oct 2026
+ 2 more near Junction 21 - see all the M25 traffic news →
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 03:02 (3:02am) Wed 14 Oct 2026