LONDON (Reuters) - Striking workers are expected back at work at the Grangemouth refinery today, helping restart a pipeline carrying half of Britain's oil, a spokesman for plant owner Ineos said yesterday.

Scotland may need to import fuel for weeks, he added.

The two-day strike over pensions at Scotland's only oil refinery, which produces a tenth of Britain's petrol and diesel, forced Ineos to close the complex last week and to cut off vital steam supplies to BP's nearby Kinneil crude oil processing plant over the weekend.

Ineos expects it will take up to three weeks to get the refinery back to normal production after the 1,200 workers return to work early today but hopes to restore power and steam supplies to Kinneil quickly so that the Forties pipeline system can reopen soon. "Forties will be the first priority for us," the spokesman said. "We will be starting up the steam into Kinneil so that can restart."

Power and steam supplies needed to reopen Kinneil should be the first part of the Grangemouth complex to restart, he said, without saying how long it would take.

The closure of Kinneil over the weekend forced Britain's Forties oil pipeline to close, cutting off almost half of the UK's oil production.

The closure of the oil and gas fields connected to the Forties pipeline network also trapped about a fifth of Britain's gas supply under the North Sea but an increase in imports from other European countries made up for it.

The plant's owners expect Grangemouth to return to full capacity in two or three weeks, while fuel tankers head for the east coast of Scotland to top up supplies in the meantime.

"We are importing refined fuels so that those can be fed into the network to help alleviate some of the disruption that this has caused," the Ineos spokesman said.

"We have a number of other tankers that are currently on the water and are making their way to Grangemouth."

The Scottish executive said an extra 65,000 tonnes of fuel — mostly diesel which is lacking in Britain — had been lined up for delivery into Grangemouth and would cover 10 days of fuel needs in the region.

But traders who supply Britain with fuels said they believed Grangemouth would need more imports over the next few weeks.

Some of diesel moving into Grangemouth had been sold for delivery into the Thames, potentially opening up supply gaps in southeast England, they added.

No more strikes are planned at Britain's Grangemouth refinery, a spokeswoman for the union Unite said yesterday.