So-called “unscrupulous employment practices” will come under scrutiny next month, as MPs debate actions by retailers to mitigate the cost of the national living wage.

MPs argue that retailers, including B&Q and M&S among others, have made cuts to workers’ benefits to offset rising salary costs since the implementation of the national living wage in April this year.

The debate, proposed by MP for Mitcham and Morden Siobhain McDonagh, has gathered the support of more than 40 MPs, including former business minister Anna Soubry.

McDonagh said: “This will be an excellent opportunity to celebrate Living Wage Week and employment practices that allow employees to have a decent standard of living.

“But we will also highlight those employers who choose to use the introduction of the national living wage to get round employment terms and reduce terms and conditions.”

A debate held in April resulted in staff at B&Q being offered a compensation term of two years instead of one, which McDonagh describes as “a direct success.”

McDonagh warned retailers earlier this year that she is “coming after them” on pay as she delivered a petition with 90,000 signatures to Marks & Spencer bosses.

The three-hour debate will take place in the House of Commons on November 3.

The national living wage is set to rise again to £9 per hour by 2020.