Devon and Cornwall Police say the M5 Northbound is likely to remain closed until 1.00am and the Southbound should re-open by 9.30pm.
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Here's everything we know so far about the Manchester Arena explosion.
Witnesses reported hearing a "huge bang" at the venue during the concert on Monday evening.
Mist and fog will not lift until the afternoon in the South West but it will warm up by the afternoon.