A strike at Britain’s third largest oil refinery could cost the economy up to £250 million, crippling infrastructure and prompting fears of fuel shortages across the country.

Gordon Brown was accused of not doing enough to avert fuel shortages caused by the strike at the Grangemouth refinery, near Edinburgh, and the suspension of nearly a third of North Sea production.

BP responded to the two-day action by starting to shut down the Forties pipeline system, which carries 30 per cent of Britain’s daily oil output from 50 North Sea oil fields. The pipeline is not expected to be working again until several days after the strike has finished. The production loss will cost the economy about £250 million.

It is the first time that the Grangemouth plant, which has been processing fuel for 80 years, has shut down in peacetime. Downing Street appealed for motorists to remain calm but petrol stations across Scotland reported growing fuel shortages and there were concerns that any panic buying could spread across the Border.

The 48-hour stoppage at Grangemouth, which also supplies fuel to Northern Ireland and northern England, will almost certainly go ahead as scheduled tomorrow. The Government faced mounting criticism last night over its failure to stop the strike.

Ministers are desperate to avoid queues at petrol stations in the week of local and mayoral elections and told motorists yesterday not to buy more fuel than normal. However, Malcolm Wicks, the Energy Minister, admitted that he could not guarantee that drivers would not be affected by shortages. “I hope the vast majority of people are sensible about this. They might have to be patient,” he said.

“There are short-term stockouts occurring at some filling stations in Scotland, but the petrol industry is confident that they can continue to resupply from stocks and imports.”

The Liberal Democrats said that the Government risked talking the country into an avoidable fuel crisis while the Conservatives accused ministers of failing to do enough to avert the strike.Talks at the conciliation service Acas collapsed on Wednesday night after the management and Unite union failed to settle a row over the company’s proposal to close the final-salary pension scheme to new employees.

Tony Woodley, Unite’s joint general secretary, told workers that there was no possibility of the strike being called off. He added: “There is no justification for what the company is proposing because it is profitable and the Grangemouth site is profitable.” He said, however, that there should be a “pause for peace” after the strike.

The Prime Minister urged Unite and Ineos, which owns the Grangemouth plant, to return to the negotiating table. Mr Brown, intervening in the dispute for the first time, said: “I think it is absolutely vital that all the parties get back to talking as quickly as possible. There was no need for a dispute to flare up here.”

Ineos accused union officials yesterday of escalating the dispute by refusing to maintain power and steam supplies needed to keep the nearby Kinneil processing plant in production.

The BP ETAP, Andrew, Bruce, Rhum, Everest and Lomond fields, which supply crude to the pipeline, will halt production. ConocoPhillips said that Britain’s largest gas field, Britannia, would be forced to close.

The Grangemouth plant has been undergoing a phased shutdown since Friday last week to ensure that it remains safe. Ineos has said that it could take up to three weeks before it is operating at full capacity again.

Although there appears no imminent danger of Scotland or northern England running out of fuel, this depends on motorists remaining calm and the availability of fuel from other sources — including from England and from elsewhere in the North Sea.

A spokesman for the UK Petroleum Industry Association said: “Scotland is not going to run out of fuel unless people go completely crazy. But that’s not to say it isn’t going to be something of a challenge to keep Scotland supplied.”

Many petrol stations said that they were running low on fuel and some had signs saying “no diesel”.

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