Scientists have called for a halt to oil drilling in Surrey after a mysterious 'swarm' of earthquakes.

Four senior geologists have said that there are risks to health and environment after 12 unexpected earthquakes hit the county in four months - after none for 50 years.

They argue that the unstable geology had not been identified at the time permission was granted for several oil exploration sites, and two are just a few miles from the earthquake epicentres.

There are worries an oil well could rupture, causing groundwater to become contaminated with oil or gas.

Affected sites include Newdigate, Horley, Dorking and Charlwood, where there have been reports of shaking ground and creaking buildings.

In a letter to The Times, the scientists wrote: "The abrupt onset of the earthquake cluster recorded by the British Geological Survey [BGS] at Newdigate since April 1 requires an explanation, and gives rise to our concerns about safety. Oil drilling, extraction and re-injection can cause earthquakes.

"There are two oil sites in the immediate area: Horse Hill and Brockham. A causal link with either well site cannot be ruled out, so we need the full picture for the risk assessment."

The scientists have called for energy secretary Greg Clark to halt drilling, testing and re-injecting water into wells until the cause of the earthquakes has been investigated.