A North Sea oil field has been closed down after a leak was discovered in a pipeline.

The Foinaven field, nearly 120 miles west of Shetland, was closed down after the "small" leak was discovered early on Sunday.

The leak, of an oil and water mix, was discovered by a remotely-operated vehicle carrying out routine checks at the BP owned field at around 1.30am.

The field was immediately shut down and the leak was stopped within an hour.

It is thought that the hairline crack appeared on the pipe sometime after January 17.

A company spokesman said it was not yet possible to calculate how much oil had leaked or how long it had been escaping for.

He said: "BP has since carried out comprehensive checks of the area, at the source and on the surface, and can confirm that no oil is visible and that there is no evidence of ongoing pollution.

"Production remains shut down. An investigation into the cause of the incident will be carried out by BP."

Coastguard, police, the Health and Safety Executive and the Department of Energy and Climate Change have all been notified.

WWF Scotland said it was time Scotland gave up its "addiction" to oil.

Director Dr Richard Dixon said: "We're relieved to hear that a potential oil pollution incident appears to have been avoided west of Shetland.

"Nevertheless, the discovery of cracks in any oil pipeline is still worrying.

"This incident once again highlights the daily threat oil drilling poses to Scotland's marine environment.

"If Scotland wants to lead the world on clean energy then the quicker we end our addiction to oil the better."