OIL is still leaking from a Shell platform in the North Sea, in what has become the worst spill in UK waters for more than ten years.
Despite assurances from the company that the leak was "under control", oil is continuing to flow from the Gannet Alpha platform about 112 miles east of Aberdeen, five days after Shell was first alerted to the problem.
Stuart Housden, director of RSPB Scotland, said figures from the Department of Energy and Climate Change (DECC) showed that the spill was the worst for more than a decade.
He criticised the energy giant's response, given the seriousness of the leak, and said the spill could put thousands of seabirds at risk.
Environment groups last night accused First Minister Alex Salmond of downplaying the scale of the problem, which he denied.
Shell yesterday said the flow of oil from the platform had been further reduced.
Figures held by the DECC show that other spills in the past ten years have involved half a tonne of oil or less. In contrast, this spill is thought to be about 100 tonnes in size, although Shell has not confirmed quantities. The company said it covered an area of about 19 miles by three miles.
Mr Housden said: "The First Minister was coming out on Friday and Saturday saying it's small.
"It is small compared to what we saw in the Gulf of Mexico, but it is the largest single leak that we've had for at least ten years from an offshore installation."
He said Shell had not provided RSPB Scotland with information despite repeated requests, and it had been impossible to assess the threat to vulnerable seabirds
"I have asked to speak to someone on the operations side of things at Shell to get a first-hand update, and I'm still waiting," he said.
"I have begun to get concerned about how difficult it is to get information out of Shell. I want to talk to them when this is all over and review the way it has been dealt with.
"I would have thought it was in their interest to be open with bodies like us, who have got experience and knowledge to impart."
Mr Housden stresses it was crucial that the RSPB was kept informed about the scale of the problems so it could advise on how to protect seabirds in the area. "Even a leak of half a tonne in the wrong place can kill hundreds, if not thousands, of birds," he said.
At this time of year, young guillemots, puffins and razorbills from colonies in Orkney, Shetland and Norway are particularly vulnerable in the North Sea. The last major oil spill in UK waters was caused by the Liberian registered tanker MV Braer, which was carrying 85,000 tonnes of crude oil when it ran aground off Shetland in 1993.
Richard Dixon, director of WWF Scotland, criticised Shell for not making the leak public until Friday - two days after it was first noticed.
"One hundred tonnes is a serious spill. Shell clearly didn't want to tell anybody about it until they had got it under control," he said.
"I think the government and most of the political parties are all desperate to be nice to the oil industry."
Shell said last night that the leak on the flowline system that serves the platform "remains under control" and an inspection by a remote operated vehicle (ROV) showed the leak rate had "reduced further".
"We are using ROVs and preparing divers as we continue to take action to reduce the leak as the weather allows, and where it is safe to do so," a spokeswoman said.
"We continue to expect the oil sheen will be naturally dispersed through wave action and will not reach shore. A stand-by vessel remains on station with oil spill response equipment and dispersant if required.
"We care about the environment and we regret that this spill has happened. We have an emergency response team on this and we are working with the relevant authorities to minimise the impact of this incident."A spokesman for Mr Salmond said the First Minister regarded all such incidents with "great seriousness".
He added: "Any leak is a serious matter, and we will support the thorough and robust investigation that will follow this incident.
"The Scottish Government is closely monitoring the situation and is being kept fully informed of any developments. Marine Scotland officials have attended Shell's Emergency Room and are participating in the operations control unit.
"Marine Scotland's role includes providing environmental advice, supporting aerial surveillance operations and ensuring all fishing vessels in the vicinity are aware of the incident."