Ed Miliband will today announce plans for a new law to stop the exploitation of workers, which leads to workers’ wages and conditions being undercut.

Speaking in Great Yarmouth, where he will host a Q & A event with voters, he will say that the next Labour government will introduce fair rules to tackle people’s concerns about the impact of immigration in our economy, our social security system and our communities.

Such concerns include the way some employers have systematically exploited people from other countries, enabling them to pay lower wage rates and offer worse conditions than for their existing workers. This leads not only to the exploitation of migrants, but the undermining of wages for local workers.

Labour has already promised to increase the fines ten-fold for firms paying below the National Minimum Wage, close down loopholes in agency worker laws that allow firms to undercut directly employed staff, ban recruitment agencies from hiring only from abroad, and calling for a new law against extreme cases of exploitation.

Today, Mr Miliband will go further by announcing how the next Labour government will stop employers exploiting foreign workers. The new law would define different forms of exploitation.

To prove that a criminal offence has been committed, evidence would have to be provided that some abuse of power had occurred and that migrants were employed on significantly different terms to local workers. For the first time, it means that undercutting of wages and conditions, although it will not be sufficient on its own, can be used as a piece of evidence of exploitation.

Extracts from Mr Miliband’s opening remarks

“I am the son of parents who came here as refugees. 

"I am proud that Britain enabled them to build a home and family.

"And I am proud of the contribution that immigrants – of all origins, races, and faiths - have made to our country.

"But when people worry about the real impact immigration has had, we will respond to those concerns not dismiss them. That is why I have changed Labour’s approach since 2010.

"People want there to be control of immigration. That means being tough on illegal immigration, with proper entry and exit checks. But control doesn’t stop at the border, it is also about fair rules when people get here.

"Fair rules means that entitlement to benefits needs to be earned. That is why we have already published proposals to prevent people coming here claiming benefit for at least two years. Fair rules means people integrating into communities and learning English.

"But it isn’t just the benefits system that needs to be fair. It is the workplace too. We know that so many workplaces are so far from being fair today. And that is especially true in many workplaces with a large number of employees who have come from overseas.

"We have all heard the most truly shocking stories of people having their wages stolen, and having to live in the most appalling conditions, exploited because they come here from abroad.

"These practices have an effect on local workers too. Because when people can be exploited for low wages or endangered at work, it drags the whole system down, undercutting the pay and conditions of people here.

"We have a plan to change this. We will increase the fines for firms paying below the National Minimum Wage. We will close down loopholes in agency worker laws that allow firms to undercut directly employed staff. We will ban recruitment agencies from hiring only from abroad.

"Today, I am announcing that the next Labour government will go further still: making it a criminal offence to undercut pay or conditions by exploiting migrant workers.

"We are serving notice on employers who bring workers here under duress or on false terms and pay them significantly lower wages, with worse terms and conditions.

"This new criminal offence will provide protection to everyone. It will help ensure that, when immigrants work here, they do not face exploitation themselves and rogue employers are stopped from undercutting the terms and conditions of everyone else.

"The choice at the next election is whether we change our economy to make it work for everyday people or carry on with an approach which means it works only for a privileged few at the top. We can’t do that unless we deal with the undercutting of wages which is made possible by the exploitation of migrant workers.

"Neither the Tories nor UKIP will do any of this.

"They turn a blind eye to exploitation and undercutting because it is part of the low skill, low wage, fast-buck economy they think Britain needs to succeed.

"We won’t make false promises on immigration, like David Cameron.

"And we won’t offer false solutions like UKIP—leaving the European union would be a disaster for jobs, business and families.

"Instead, we will offer clear, credible and concrete solutions which help build a country that works for working people again.”