Meanwhile, the coastguard was not alerted to the Purbeck Isle's plight for seven hours as it was not fitted with an emergency position-indicating radio beacon or similar distress signalling device.

BBC: Purbeck Isle deaths report: Life raft failures blamed

More modern versions of the tool add in a laser beam projector, which allows builders to level out the device and "draw" a long line of light across a wall, indicating an exactly level surface.

FORBES: No. 18 The Level