BP has spilled hundreds of barrels of oil in the North Sea, in a leak from its Clair platform.
The energy giant said the leak was stopped within an hour of being spotted on Sunday morning and it had temporarily shut down the platform, 46 miles west of Shetland, while it investigated the precise cause.
It estimated that 95 tonnes of oil, equivalent to more than 665 barrels, had been released during the leak, which left oil visible on the surface of the sea.
BP said that the slick appeared to be moving northwards away from land and it believed that "the most appropriate response is to allow the oil to disperse naturally at sea", though it was preparing "contingencies for other action".
A spokesman said the leak had been caused by "a technical issue with the system designed to separate the mixed production fluids of water, oil and gas".