Workers at the Lindsey refinery explain why they will stay out 'for as long as it takes'
Hundreds of workers are continuing unofficial strike action over the use of foreign contractors, as talks resumed to try to resolve the dispute.
Protesters gathered outside Lindsey Oil Refinery - where the wave of strikes originated last week - saying they were awaiting the outcome of the Acas talks.
Some 600 workers walked out of Langage power station near Plymouth on Tuesday.
Workers in Fife, Cheshire, North Yorkshire, Essex and Hampshire have continued their support protests.
The CBI has backed the company at the centre of the dispute against union claims that it has discriminated against British workers.
Meanwhile, Labour MPs and union leaders have dismissed claims that striking workers are guilty of xenophobia.
Unfortunately over the last day or two we have heard a lot of talk about xenophobia
Jon Cruddas, Labour MP
Dagenham MP Jon Cruddas said people should focus on the issues at stake, principally the need for employers to respect local employment agreements as well as national pay deals.
"Unfortunately over the last day or two we have heard a lot of talk about xenophobia," he said.
"I am afraid that does not respect some of the issues that are at work here and that sort of language builds up the problem rather than acknowledges the nature of the problem."
Derek Simpson, the joint leader of Unite, said: "The unofficial action taking place across the UK is not about race or immigration, it's about class.
"It's about employers who exploit workers regardless of their nationality by undercutting their hard won pay and conditions."
A Labour MP has put down a Commons early day motion (EDM) "deploring" the use of foreign workers at the Lindsey refinery, which is owned by Total.
The motion from John Mann - MP for Bassetlaw, Nottinghamshire - congratulated unions for "exposing this exploitation and the absence of equal opportunities to apply for all jobs".
The MP also said imminent large capital projects - such as new power stations - should be built by "companies employing primarily British labour on decent pay and conditions".
Mr Mann called on the mediator to also investigate a contract at the new Staythorpe power station in Newark, Nottinghamshire.
Talks on the dispute - which began on Monday - have resumed at a hotel near Grimsby between the mediation service Acas, Total managers, the main contractor Jacobs, and union officials.
An official said on Tuesday Acas was unlikely to provide a report on the strike before next week.
About 500 protesting contractors at Grangemouth oil refinery in central Scotland returned to work on Tuesday.
Contractors at Longannet power station in nearby Fife voted to continue their support and will meet again on Friday.
Up to 500 workers at Shell's Stanlow refinery, Cheshire, walked out but no protests are being held and workers are believed to be expected back on Wednesday.
1. Stanlow oil refinery
2. Longannet power station
3. Drax power station
4. Coryton oil refinery
5. Langage power station
6. Marchwood power station
7. Fawley oil refinery
8-12: Torness power station ; Mossmorran chemical plant ; Aberthaw power station ; South Hook natural gas terminal ; ICI chemical refinery 
13-17: Corus steel plant ; Fiddler's Ferry power station ; AES Kilroot power station ; Cockenzie power station ; Sellafield nuclear site 
18-22: Heysham nuclear power station ; Staythorpe power station ; Didcot power station  Grangemouth oil refinery ; St Fergus gas plant 
Some workers at Drax Power Station, near Selby in North Yorkshire, have also continued to strike in support of the dispute, following a walk-out by 150 contractors there on Monday.
Drax said the action was having no impact on power generation.
About 250 contractors - mainly maintenance workers - at Coryton oil refinery in Thurrock, Essex, have continued their solidarity action.
About 300 workers in Hampshire have also supported the action, with continued action at an Esso refinery in Fawley and at Marchwood Power Station.
Thousands of contractors and unemployed workers protested last week and on Monday in a series of unofficial walk-outs around the UK, to show solidarity with workers protesting at the use of Italian and Portuguese labour at the Lindsey refinery.
Workers there were angry that a contract for work to expand the refinery was sub-contracted by Total's main contractor - engineering firm Jacobs - to an Italian company, IREM, which decided to use its own workforce.
Total insists it is not discriminating against British workers, and that the decision to award the contract was fair.
Speaking from the crowd of protesters at the Lindsey site in North Lincolnshire, strike committee member Phil Whitehurst said he and his colleagues were convinced of their case.
He said they had nothing against the Italian workers at the centre of the dispute.
"People have said it's racist. It's not. We're not part of the BNP. I've shunned the BNP away from here.
"It's about British workers getting access to a British construction site."
The protesters later dispersed, agreeing to reconvene at 0700 GMT on Wednesday.
On Monday contractors at two UK nuclear plants - Sellafield and Heysham - joined the dispute with a "sympathy strike".
Workers at Grangemouth oil refinery, central Scotland, and power stations in Longannet, Warrington, and Staythorpe in Nottinghamshire were also among those to walk out.
Meanwhile, CBI deputy director general John Cridland told MPs there was no evidence of any discrimination and no need for any change in EU law to safeguard British workers.
He said: "As far as we are aware they [the company] are operating lawfully."
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