One lane is closed northbound on the M5 between J19 (Portishead) and J18 M49 (Avonmouth). It's causing congestion right back to J20 (Clevedon).
It happened after a caravan became detached from the car towing it. Three lanes have re-opened but lane one remains closed.
More top news
Military personnel are unlikely to be deployed on the streets of Avon and Somerset despite an increase in the national terror threat level.
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.
The threat level has been raised to critical by MI5's Counter-Terrorism Analysis Centre.