Unite claims some employers are still excluding UK workers
A protest march has been held over the use of foreign workers at a Nottinghamshire power station.
Unite union general secretary Derek Simpson led workers at Staythorpe, near Newark, on Tuesday.
He said local workers were not being considered for jobs by contractor Alstom, which has denied the claim.
Another protest was held at the Isle of Grain power station in Kent. The issue prompted walkouts at more than 20 sites across the UK last month.
This centred on the Lindsey Oil Refinery in Lincolnshire after Italian workers were brought in to carry out a contract.
We do provide British jobs for British workers
Alstom's UK President, Stephen Burgin
The wildcat strikes ended after a deal on the use of foreign labour but Unite said the issue had not been completely resolved.
Mr Simpson said: "The government must act now to level the playing field for UK workers."
He urged the government to insist companies applying for contracts on public infrastructure projects sign up to corporate social responsibility agreements committing contractors to fair access for UK labour.
He said: "The UK needs to upgrade and build new power stations and there are huge opportunities to create thousands of well paid and highly skilled jobs.
"It will be a disgrace if UK workers are not even allowed to apply for jobs to build British power stations.
"No European worker should be barred from applying for a British job and absolutely no British worker should be barred from applying for a British job."
Contractors have insisted UK workers are not being overlooked for jobs at the two sites.
Alstom's UK President, Stephen Burgin, said: "The fact is, we do provide British jobs for British workers and we're proud to do so. We understand the concerns of protesters, however, Alstom has no say or control over EU employment law.
"We're a company that works within the law and wants to continue investing in the UK and training and recruiting British workers."
Mr Burgin said the company had spent several thousand pounds building training centres in Stafford and Rugby. He added they take on 30 apprentices a year in the UK and will employ 120 apprentices by the end of 2009.
Mr Simpson said he now wants to organise a national march through London to put pressure on the government.
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