Unions should be able to report employers who fail to pay the new minimum wage to the Inland Revenue as workers are often afraid to make official complaints, according to the GMB.

Paul Kenny, GMB general secretary, says: "There is also an issue about enforcement. Workers are prepared to give evidence to GMB where they are being paid less than the national minimum wage and give details of the employers and place of work and other details. But often if they provide evidence to the Inland Revenue they are likely to be sacked or victimised by the very rogue employer who has been under paying them and then they are even worse off. This in particular applies to migrant workers.

“For years now, GMB has been asking the government for the ability of trade unions to give the necessary evidence to the Inland Revenue on behalf of the vulnerable workers which at present we are not able to do. This is an obvious and simple change in the reporting regulations that would help enforce the law and save the jobs of workers who are the lowest paid in the land."

The minimum wage increased yesterday from £5.35 to £5.52 an hour for workers aged 22 and over. There will also be increases from £4.45 to £4.60 for 18-21 year olds, and from £3.30 to £3.40 for 16-17 year olds.