Highways England has released advice for drivers travelling south on the M5 after an incident early this morning.
It says it expects the motorway to reopen "early this evening".
The M5 in Somerset remains closed southbound this afternoon between J19 and J20 following a multi-HGV collision incident.
"Customers should be aware there are two specific diversion routes for traffic, both routes follow the hollow circle diversion symbol.
HGV traffic is advised to exit at J18. Join the A4 eastbound for approximately 5 miles, and then join the A370. Continue on the A370 southbound for approximately 14 miles to then rejoin the M5 at J21.
Non-HGV traffic should leave the M5 at J19 and join the A639 eastbound for approximately 5 miles until the roundabout with the A370. Take the A370 southbound for approximately 14 miles, and then rejoin the M5 at J21.
Please allow extra time for your journey should you be travelling in the area."