Workers at the Grangemouth refinery in Scotland returned to work on Tuesday after a two-day strike which closed the plant and the Forties North Sea oil pipeline, an official at the UNION trade union said.

"The strike is finished. The guys are back in work", said Mark Lyon, a spokesman for the union.

The plant's 1,200 workers walked out on Sunday morning in a dispute with refinery owner Ineos over pensions.

The closure of the refinery, which produces about 10 percent of the UK's petrol, led to fuel shortages in Scotland as motorists rushed to fill their tanks and prompted emergency fuel shipments from Europe to top up local supplies.

The closure of the refinery and Forties pipeline helped drive oil on Monday to a fresh record high near $120 a barrel.

Ineos has said restoring oil supplies through the 700,000 barrel a day Forties pipeline system, which carries about half the UK's North Sea crude output, is a priority.

The pipeline had to close as its Kinneil oil processing plant receives steam and power supplies from the Grangemouth refinery but these were cut during the strike.

Forties operator BP said that assuming supplies from Grangemouth were restored as soon as the strike ended and the Forties fields restarted production rapidly, the pipeline could be back in operation in 24 hours but might take a few more days to get back to full flow.

Ineos has said it could take up to three weeks to resume full production at the 200,000 barrel a day refinery, but the union has said full output could be restored within a week to 10 days.