PRESS ASSOCIATION -- Oil is continuing to spill from a pipe below a platform in the North Sea, days after operator Shell said the problem was under control.
An estimated 218 tonnes of oil - equal to about 1,300 barrels - has so far leaked from the pipe near the Gannet Alpha platform, about 112 miles east of Aberdeen.
An initial large leak was stopped on Thursday, but it has emerged that a smaller flow from the same source had been detected.
Shell, which has been heavily criticised by environmental groups for the way it is handling the problem, said the secondary leak is in an awkward place surrounded by marine growth.
The leak is the biggest in the North Sea for a decade. The total amount of oil discharged in 2009 was 50.93 tonnes.
Glen Cayley, technical director of Shell's exploration and production activities in Europe, said the rate of leakage has declined to one barrel a day. The oil sheen on the sea covers an area of about 16 square miles, estimated somewhere between one and 10 tonnes in volume. Shell says it is not thought the oil will reach land.
Mr Cayley said: "We believe that the small leakage is coming from a relief valve adjacent to the main leak and from the same source. Once we've confirmed this, we will develop a series of mitigation options to stop this remaining leak.
"It has proved difficult to find the exact source of the leak because we are dealing with a complex subsea infrastructure and the leak seems to be coming from an awkward place surrounded by marine growth. So it has taken our Remote Operated Vehicle inspections some time to establish exactly where the source is."
Responding to concerns for the welfare of wildlife in the area, he said: "To date, our observers, who are constantly assessing bird life in the area, report little bird activity and no visible damage to wildlife. We will continue to monitor the area and inform the RSPB."
The Scottish Government said a fishery research vessel will take fish, seawater and sediment samples to monitor any environmental impact from the leak. Environment Secretary Richard Lochhead said: "There are currently no Scottish fishing vessels operating close to the vicinity of the oil leak, therefore no impact is expected in terms of contaminated fish entering the food chain, but we remain vigilant."