M1 | Greater London | Road Closure | Expect Delays

Incident timeline

1. 21:08, 17 AugFirst report

   The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

2. 22:36, 17 AugUpdate

   The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

3. 23:06, 17 AugUpdate

   ⏱ Still active — no changes from National Highways. Incident ongoing for 1h 58m. Monitoring continues.

4. 23:11, 17 AugUpdate

   The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

5. 23:41, 17 AugUpdate

   ⏱ Still active — no changes from National Highways. Incident ongoing for 2h 33m. Monitoring continues.

6. 23:46, 17 AugUpdate

   The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

7. 00:16, 18 AugUpdate

   ⏱ Still active — no changes from National Highways. Incident ongoing for 3h 8m. Monitoring continues.

8. 00:21, 18 AugUpdate

   The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

9. 00:21, 18 AugUpdate

   ✅ Incident cleared — M1 reopened at 00:21 on 18 Aug 2026. Total disruption: 3h 13m. All lanes open, traffic returning to normal.

10. 09:15, 6 NovFinal update

    The M1 in Greater London is closed in both directions between J4 (near Borehamwood) and J1 (near Wembley) for a police led incident

Wording from National Highways, recorded as it changed.

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