M4 closed J20–J21 westbound

Road closure on the M4 westbound at J20–J21 on Saturday 26 September 2026, from 22:43. Cleared at 04:51 after 6 h 8 min. Timeline of reports from National Highways.

Status

Cleared 04:51 on 27 Sept 2026, after 6 h 8 min

Location

M4 westbound · J20–J21

Reported as

Road closed · cause not reported yet

Lanes

Road closed

Sources

National Highways

Timeline

1. Sat 22:43 National Highways: road closed
2. Sun 04:51 National Highways: road reopened
3. Sun 04:51 All clear: no source reports it any more

Source reports

• M4 westbound between J20 and J21

Other recent incidents on the M4

• M4 crash J18yesterday 19:23 · cleared after 46 min
• M4 crash J5–J4B eastboundyesterday 18:15 · cleared after 57 min
• M4 closed J15–J16yesterday 17:50 · cleared after 15 min
• M4 crash J19–J20 westboundyesterday 16:33 · cleared after 1 h 19 min
• M4 reported crash J13–J12 eastboundyesterday 08:00 · cleared after 38 min
• M4 crash Westboundyesterday 07:57 · cleared after 2 h 30 min
• M4 crash Eastboundyesterday 07:57 · cleared after 45 min
• M4 crash J35 eastboundyesterday 07:27 · cleared after 2 h 55 min
• M4 reported crash J15–J14 eastboundMon 22:41 · cleared after 54 min
• M4 crash J8–J10 westboundMon 18:25 · cleared after 46 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.