M4 closed J20–J21 westbound

Live Still reported at 23:14 UK time, since 20:56 (2 h 18 min).

Road closure on the M4 westbound at J20–J21 on Monday 28 September 2026, from 20:56. Still reported at 23:14 UK time. Timeline of reports from TomTom and National Highways.

1. ✕

   M4 westbound · J20–J21

   Road closed

   since 20:56 (2 h 18 min)

   TomTom ×3 · National Highways

See the M4 on the live map M4 traffic now

Timeline

1. 20:56 National Highways: road closed
2. 21:01 TomTom: queueing traffic, “Slow traffic, Lane closed”, delay ~3 min
3. 21:02 TomTom no longer reports it
4. 21:02 All clear: no source reports it any more
5. 21:56 TomTom: queueing traffic, “Slow traffic”, delay ~4 min
6. 22:19 TomTom no longer reports it
7. 22:32 TomTom: road closed
8. 23:09 TomTom: “Bridge closed”

What the sources said

• Slow traffic, Lane closed
• M4 westbound between J20 and J21
• Slow traffic
• Bridge closed

Other recent incidents on the M4

• M4 closed J19–J20 westbound · 22:41, still reported
• M4 closed J19 westbound · 22:41, still reported
• M4 closed J16–J17 westbound · 22:41, still reported
• M4 closed J12–J13 westbound · 22:40, still reported
• M4 closed J13–J14 westbound · 22:40, still reported
• M4 closed J15–J16 westbound · 22:40, still reported
• M4 crash J12 eastbound · 22:31, cleared after 37 min
• M4 crash J13–J12 eastbound · 21:22, still reported
• M4 crash J10–J8 eastbound · 08:26, cleared after 1 h 10 min
• M4 crash J8 eastbound · 08:26, cleared after 1 h 10 min

About this page

This page shows what the data sources reported about this event and when, merged from every source that reported it at the same place. It doesn't say what caused it or whether anyone was hurt: no source reports that. Times are UK time. For live alerts, follow @motorways.me on Bluesky.