Motorists appeared to be heeding pleas not to panic-buy fuel yesterday as preparations were made for the shutting down of a third of Britain’s oil output.

Long queues formed outside some petrol stations in Scotland and an estimated 50 ran out of fuel. All were restocked within eight hours but the government urged the public to avoid nonessential car trips.

There were only sporadic outbreaks in England of motorists stocking up ahead of today’s strike by 1,200 workers at the Grangemouth refinery near Edinburgh. It is the dominant supplier in Scotland and northern England down to Lancashire and Yorkshire.

Meanwhile, coastal tankers brought fuel from Rotterdam in Holland and Gothenburg in Sweden to cover demand during the 48-hour strike, sparked by a pension dispute.

Ineos, the plant’s owner, closed it on Friday in preparation for the strike. BP’s Forties pipeline, a vital artery in Britain’s oil production network, was due to close down overnight.

This means that other refineries will have to be supplied by imports or reserves.

John Hutton, the business secretary, yesterday advised the public that there was “plenty of petrol and diesel” although stocks could be run down “if people change the way they consume fuel.” He added: “There is every reason to believe that we will get through this period sensibly if people continue to buy fuel sensibly, too.”

In Scotland the Ministry of Defence confirmed that it had been involved in discussions over the possible use of troops if it became necessary to safeguard supplies for vital services.

The Conservatives accused the government of exacerbating the difficulties by “dithering”. UK Oil and Gas, the production industry body, called on ministers to intervene at “the highest level” to resolve the crisis.

It may be three weeks before Grangemouth reaches full production again, although supply from the Forties pipeline can be reinstated within 48 hours.

However, Unite, the union behind the strike, has not ruled out further action.

Hutton said that if supplies did dip dramatically, a national emergency plan drawn up after the petrol blockades of 2000 could be put into action.

Under the plans the government would take over the supply of fuel, prioritising the emergency services, public transport and food hauliers. In addition ministers could impose a £15 limit at the pumps for each car and £150 for each lorry.

A spokesman for the Department for Business, Enterprise & Regulatory Reform said ministers were satisfied with assurances from the oil industry that there are sufficient stores and imports to cover Britain’s fuel needs.

Louise Doherty, spokeswoman for PetrolPrices.com, a consumer website, said that there was evidence of “blatant profiteering” on forecourts. One petrol station near Inverness was charging 119.9p a litre for petrol and 131.9p for diesel, 10% higher than the UK average. Some garages were rationing petrol this weekend with £10 and £20 limits.

Doherty said: “It appears some petrol forecourts are taking advantage of the fact that motorists are panicking and desperate to fill their tanks.

“Motorists need to be wary and shop around to find the best deals.”

In England there were reports of queues in North Yorkshire, Gateshead, East Anglia and Surrey. Petrol retailers yesterday reported increased sales but said there was no problem with supply. Total reported a 5% rise in sales in the northeast.

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