Seven helicopters were called to the platform

An evacuation was launched from the Thistle Alpha platform, 120 miles north east of Sumburgh, Shetland, after smoke and flames were seen after 0800 GMT.

Seven helicopters and an RAF Nimrod aircraft were alerted and helicopters began carrying those on board to other platforms in the area.

The fire was extinguished by 1045 GMT. All crew were said to be safe.

Helicopters from the RAF, coastguard and other platforms in the area had earlier been sent to the scene along with two Norwegian helicopters.

A Nimrod was also scrambled from RAF Kinloss to co-ordinate the operation.

A spokesperson for Petrofac, an international service provider to the oil and gas industry, told BBC Scotland a fire was detected in the turbine module at 0807 GMT.

All personnel on board were called to muster and as a precaution, non-essential personnel were taken to the nearby Murchison and Dunlin platforms. That left 43 essential personnel still on board.

All 159 personnel were said to be "safe and well" after it had been confirmed that the blaze had been extinguished.

A spokeswoman for the Health and Safety Executive (HSE) said the platform underwent inspections in May and earlier this month and another one is due in December. It is not thought that any serious problems were found.

The platform is operated by Swedish-based Lundin Petroleum, which is involved in oil exploration and production across the globe.

The fact they were taken off by helicopter to local platforms suggests it was a precautionary measure

Jake Molloy

OILC union

Rescuer tells of fears

Michael Mulford of RAF Kinloss said he believed the Norwegian helicopters, which were the first to arrive, had been able to land on the platform itself to pick up crew members.

He said it was "quite unusual" for a full evacuation to be ordered so quickly.

Mr Mulford added: "Normally what they will try and do is take off non-essential staff first but they have gone for a fairly major airlift from the first moment."

He said the Thistle oil field was "just about as remote as it gets - about five or six miles inside the UK search and rescue region".

Weather conditions in the area had been described as "not great", with strong north westerly winds and "reasonable" visibility.

The platform is operated by Swedish-based Lundin Petroleum

"Ideally you don't want people in the water itself. If they take to the rescue boats that is a different matter but by the sound of it the two Norwegian helicopters have managed to get to the platform itself," Mr Mulford said.

Jake Molloy, of the OILC union, told the BBC Scotland news website: "I have been trying to contact the guys but it's difficult.

"The fact they were taken off by helicopter to local platforms suggests it was a precautionary measure.

"The Thistle has a reasonable record over the last few years. There has been nothing major."

Graham Tran, of Amicus, said: "They took the decision to evacuate, that gives an indication of concern."

North Sea oil companies were told last week that more must be done to improve their offshore safety record. It followed a three-year investigation by the HSE.

Inspectors focused in particular on the safety and integrity of almost 100 offshore installations and their equipment.

Industry body Oil and Gas UK said the report highlighted the need for more work to be done, despite recent investment in maintenance.