One day, they found an irregularly shaped stone, about the size of a tea tray, its upper surface pitted with small hemispherical holes.

NEWYORKER: The Sanctuary

The Highways Agency has put up a sign warning drivers about the pitted and broken road surface on the southbound carriageway, just after junction 23 at Bridgwater North.

BBC: Condition of M5 near Bridgwater raises concerns