The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
RoadM4
SeveritySevere
StatusCleared
DirectionBoth directions
Started20:49, 18 Jul 2026
Cleared23:30, 18 Jul 2026
Incident timeline
First report
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 45 minutes. Monitoring continues.
Update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 1h 20m. Monitoring continues.
Update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 1h 55m. Delays of 60 minutes still recorded. Monitoring continues.
Update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
⏱ Still active — no changes from National Highways. Incident ongoing for 2h 30m. Delays of 60 minutes still recorded. Monitoring continues.
Update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Update
✅ Incident cleared — M4 reopened at 23:30 on 18 Jul 2026. Total disruption: 2h 40m. All lanes open, traffic returning to normal.
Final update
The M4 westbound in Wiltshire is closed between J16 (near Swindon) and J17 (near Chippenham) following a serious collision that occurred approx. 20:05 this evening. Traffic on the eastbound carriageway is also being held at this time.
Wording from National Highways, recorded as it changed.
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