CONSTRUCTION workers protesting against the use of migrants to undercut local labour in north-east England were threatened with arrest yesterday.

Waste giant Sita, which touts its credentials as a “environmentally responsible” company, has saved £4 million in labour costs through employing eastern European migrants at £5 below rates agreed with the existing workforce and excluding local workers from employment.

The company was awarded a £1.18 billion 30-year contract by Merseyside Recycling and Waste Authority.

Its new plant on the Wilton International chemical site in Redcar will burn 430,000 tonnes of rubbish a year to produce electricity for 63,000 homes.

General union GMB, which represents workers on the Wilton site, said that migrant labourers had been specifically instructed to avoid contact with union reps.

“Sita has not listened to previous protests and is not playing fair by the Teesside workforce,” said GMB national officer for construction Phil Whitehurst.

“Sita has discriminated against them by giving them no chance to get up to three quarters of the 400 jobs on the site at the construction phase of the job.

The “social dumping” of migrants is likely to emerge as a key issue for trade unionists in the run-up to Britain’s referendum on EU membership.

As part of the Teesside Construction Committee, GMB has organised a series of demonstrations in protest over bosses’ use of migrants to undercut the local workforce.

But Mr Whitehurst made clear that the union’s issue was “not about the migrant labourers themselves.”

At the ninth protest on the site yesterday, workers leafleting outside were threatened with arrest, according to the union. “At one gate the police were being very heavy handed,” Mr Whitehurst told the Star. There’s no need to have police on such a peaceful protest.”

Mr Whitehurst said that a Sita representative had told police to “back off” and the leafleting continued peacefully. A police spokesperson said: “Cleveland Police responded to this protest spontaneously as we had been given no prior warning of the intended action.”

Sita did not respond to a request for comment.