What happened
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
RoadM40
SeveritySevere
StatusCleared
DirectionSouthbound
Started02:14, 10 Jul 2026
Cleared06:00, 10 Jul 2026
Incident timeline
First report
The M40 is closed northbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
The M40 is closed northbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 51 minutes. Monitoring continues.
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 1h 26m. Monitoring continues.
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 2h 1m. Monitoring continues.
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 2h 36m. Monitoring continues.
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 3h 11m. Monitoring continues.
Update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 3h 46m. Monitoring continues.
Update
✅ Incident cleared — M40 reopened at 06:00 on 10 Jul 2026. Total disruption: 3h 46m. All lanes open, traffic returning to normal.
Final update
The M40 is closed southbound between Junction 1a (M25) and J1 (Denham) for emergency resurfacing. 
Wording from National Highways, recorded as it changed.
UK Traffic Updates