At least nine people have been arrested as protesters grind motorways to a halt in a "go-slow" campaign over the rising cost of fuel.
Eight were arrested for driving slower than 30mph on the M4 near the Prince of Wales crossing while a ninth was arrested for "unsafe driving" on the A38 in Cornwall.
At least 100 police officers scrambled to the westbound carriageway where the bridge has been closed in both directions due to the protests.