M4 closed J20–J21 westbound

Road closure on the M4 westbound at J20–J21 on Sunday 27 September 2026, from 19:52. Cleared at 05:15 after 9 h 23 min. Timeline of reports from National Highways and TomTom.

Status

Cleared 05:15 on 28 Sept 2026, after 9 h 23 min

Location

M4 westbound · J20–J21

Reported as

Road closed

Lanes

Road closed

Sources

National Highways ×2 · TomTom

Timeline

1. Sun 19:52 National Highways: road closed
2. Sun 20:55 TomTom: queueing traffic, “Stationary traffic”, delay ~12 min
3. Sun 21:00 TomTom no longer reports it
4. Sun 21:03 National Highways: road closed
5. Sun 21:09 TomTom: queueing traffic, “Stationary traffic”, delay ~11 min (reported again)
6. Sun 21:14 TomTom no longer reports it
7. Mon 05:15 National Highways: road reopened
8. Mon 05:15 All clear: no source reports it any more

Source reports

• M4 westbound between J20 and J21
• Stationary traffic

Other recent incidents on the M4

• M4 crash Both directions08:08 · cleared after 1 h 5 min
• M4 stopped traffic J3 westbound06:48 · cleared after 3 h 3 min
• M4 crash J6 westboundyesterday 15:41 · cleared after 1 h 35 min
• M4 crash J10–J8 eastboundyesterday 07:50 · cleared after 2 h 6 min
• M4 stopped traffic J20–J21yesterday 07:29 · cleared after 1 h 23 min
• M4 stopped traffic J4–J3 eastboundyesterday 06:44 · cleared after 3 h 3 min
• M4 crash J18Tue 19:23 · cleared after 46 min
• M4 crash J5–J4B eastboundTue 18:15 · cleared after 57 min
• M4 closed J15–J16Tue 17:50 · cleared after 15 min
• M4 crash J19–J20 westboundTue 16:33 · cleared after 1 h 19 min

Live traffic and past incidents at M4 J20 and M4 J21.

The sources don't report causes or injuries, so neither does this page. Times are UK time. For alerts, follow @motorways.me on Bluesky.