Ed Miliband will announce plans today to criminalise employers who undercut wages by exploiting migrants.

Speaking in Great Yarmouth, where he will host a question and answer event with voters, the Labour leader pledged to introduce a new law to stop exploitation of workers that leads to workers’ wages and conditions being undercut.

He will highlight how 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, Mr Miliband will say.

“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.”

The new law, which would be introduced if Labour won the next general election, would define different forms of exploitation.