Fifteen hundred workers staged mass walkouts across Scotland as a protest over jobs being given to foreign workers.

Seven hundred workers from Grangemouth oil refinery were amongst those who stopped work on Friday.

The mechanical contractors, who work for BP and INEOS, took the action after a union meeting held at 8am.

Another five hundred workers walked out at Scottish Power's Longannet power station on Friday, with a further one hundred workes at its Cockenzie power station and eighty people at British Energy's Torness power station also stopping work.

At the Shell St Fergus gas processing plant in Aberdeenshire, about fifty workers downed tools while about hundred people who work at ExxonMobil's petrochemicals plant in Mossmorran in Fife and some workers at the Shell plant in Mossmorran also stopped.

The action follows similar labour protests in England and Wales. Workers there are angry over the decision to bring in hundreds of Italian and Portuguese contractors to work on a new £200million plant at the Lindsey Oil Refinery in North Lincolnshire.

Some employees have been out of work since Wednesday as the dispute spreads.

Bobby Buirds, a regional union officer for Unite in Scotland, said the workers at Grangemouth were striking to protect British jobs.

He said: "The argument is not against foreign workers, it's against foreign companies discriminating against British labour.

"If the job of these mechanical contractors at INEOS finishes and they try and get jobs down south, the jobs are already occupied by foreign labour and their opportunities are decreasing.

"This is a fight for work. It is a fight for the right to work in our own country," Mr Buirds said. "It is not a racist argument at all."

The dispute at the Total Lindsey Oil Refinery has led to scenes reminiscent of the industrial disputes of the 1970s with hundreds of placard-waving protesters watched by ranks of police.

Workers walked off the site on Wednesday following weeks of discontent over the contract to build the £200million HDS-3 de-sulphurisation unit.

The dispute erupted after Total put the contract to build the new unit, which will allow the refinery to process crude oil with a higher sulphur content, out to tender.

Total hopes the plant will give the refinery the capacity to process oil even when North Sea reserves begin to dwindle.

Five UK firms and two European contractors tendered for the work. It was awarded to the Italian company Irem on the basis that it was supplying its own permanent workforce.

It is understood 100 Italian and Portuguese workers are on the site. They are expected to be joined by 300 more next month.

Derek Simpson, joint leader of Unite, called for urgent meetings with the Westminster Government and employers to discuss the "exclusion" of UK workers from some of Britain's major engineering and construction projects.