The M5 Southbound between junctions 25 and 26 (Taunton) is expected to stay closed until at least 11am.
It's following a crash in which a man in his 20s died. Another two people have been taken to Musgrove Park hospital in Taunton in a life threatening condition. All were travelling in the same car.
Police are appealing for witnesses to the crash.
Motorists are being advised to take alternative routes.
More top news
Remember the pensioner targeted by vandals because his yellow car spoiled the picture postcard view? He's now got a colour named after him
Cases include that of Max the Westie who was left to suffer with a tumour so bad it was described as ‘like something out of a horror film’
A fair amount of rain overnight but that should pass tomorrow morning. There won't be much sunshine but temperatures could reach 18 C