An earthquake of that magnitude would cause general alarm

Alice Walker BGS

The last one was in 1990, when an earthquake measuring 5.1 rocked Bishop's Castle in Shropshire.

The BGS's head seismologist, Alice Walker, warned: "We are overdue for another magnitude five.

"An earthquake of that magnitude would cause general alarm."

In 1984, a 5.4 magnitude tremor in Lleyn, north Wales, felled chimney pots 100 miles away in Liverpool, Miss Walker added.

Fault lines

She said the UK was "riddled" with fault lines but it was difficult to associate earthquakes with particular lines because they ran so deep.

The Cornwall quake is thought to have happened 17 miles underground.

Earthquakes in the Channel can affect London - but the capital has not been the epicentre of one since a 3.5 magnitude tremor in the mid-18th Century.

Places in the UK that are particularly at risk are Scotland and the west of England.