More than 1500 Scottish contract workers joined thousands around Britain as wildcat strikes in protest against foreign labour escalated yesterday.

Around 1500 contract workers from the Sellafield nuclear site in Cumbria, 300 at the Heysham nuclear power station in Lancashire and further staff at Staythorpe, in Nottinghamshire, joined the unofficial action over the hiring of Italian and Portuguese workers on a Lincolnshire power station project.

Some 500 from Longannet power station in Fife joined 700 at the Grangemouth oil refinery, who voted to continue their strike, while 200 employees at Fiddlers Ferry power station in Widnes, Cheshire, also walked out yesterday morning.

The escalation came as talks aimed at resolving the dispute showed little sign of an early breakthrough.

Despite blizzard conditions, hundreds of workers gathered outside Total's Lindsey Refinery in North Lincolnshire where the dispute began when a £200m construction contract was handed to an Italian firm, IREM, which then brought in Italian and Portuguese workers.

Total yesterday insisted it is not discriminating against British workers.

A statement said: "We recognise the concerns of contractors but we must stress that it has never been, and never will be, the policy of Total to discriminate against British companies or British workers."

Unite, Britain's biggest trade union, said the government was "failing to grasp the fundamental issues" behind the unofficial strikes taking place throughout the country.

The mediation service Acas met with Total managers, its main contractor Jacobs, and union leaders for talks in Scunthorpe yesterday.

The talks were adjourned and will resume today after agreeing the terms of reference, which involves studying the contract at the heart of the row.

A small group of protesters congregated close to the Forest Pines Hotel where the talks were understood to be taking place. Police were guarding both entrances.

At Longannet and Grangemouth, where workers held meetings yesterday morning, it was expected staff would return to work this morning.

Joining Longannet and Grangemouth workers in stoppages in Scotland were 150 at Shell's petrochemicals plant in Mossmorran, Fife, and 80 from Exxon Mobil's neighbouring plant. A further 130 took action at ScottishPower's Cockenzie power station.

Bobby Buirds, regional officer for Unite in Scotland, said: "We understand there are smaller sites in Scotland that have gone out in support of the dispute and have not officially contacted us "That's the kind of emotion that is building up over this. The general feeling is that because nothing has happened about the discussion taking place the lads felt it would be unfair to leave them on their own."

Unite has put forward a three-point plan for dealing with the unofficial strike action. Joint leader Derek Simpson said the immediate problem should be tackled, an investigation launched into the practices of contractors and moves should be taken to overturn European legal precedents which he maintained allowed employers to undercut wages and conditions.

Paul Kenny, leader of the GMB union, said the government was now inching towards the hub of the problem.

"It cannot be right that companies can import workforces and deny access to jobs to UK workers. We have evidence of this happening on other contracts. What the Prime Minister and Peter Mandelson are saying is not what is happening on the ground."

At a mass meeting involving more than 1000 demonstrators outside the Lindsey refinery, Kenny Ward from Unite said: "Over the last week, your heroic actions here have inspired thousands in our county, hundreds of thousands in our country, and millions across the globe."

Around 600 mechanical contractors, around half of those who "downed tools" at Sellafield yesterday, gathered at a nearby car park to discuss the need for the action.

They include scaffolders, riggers, pipefitters and labourers working on building projects around the site.

A Sellafield spokesman said there were very few foreign workers employed at the site and 90% of contractors were from west Cumbria.

The industrial action is scheduled to last for 24 hours and contract workers were expected to reconvene at 7.30am next Tuesday to reassess the situation.

A spokesman for the Energy Department said: "We're not aware of any current or potential impact of the unofficial strikes on gas, electricity or fuel supplies."

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