The Labour government is to back a private members bill to protect migrant construction workers from exploitation

Jim Sheridan, the Labour MP for Paisley and Renfrewshire North, proposed extending the Gangmasters (Licensing) Act to cover construction last year, but now Harriet Harman, the deputy Labour leader, is believed to have taken a personal interest.

Harman is the first Cabinet minister to put her weight behind the legislation. She is reportedly committed to extending the act in the next parliamentary session, and is actively lobbying colleagues for support.

Harman is married to Jack Dromey, the deputy secretary of union Unite, who has been a driving force behind extending the legislation to construction.

A source said: “Harman has been very helpful. It is something she’s committed to.”

Harman has been very helpful. It is something she is committed to.

A union source

The Gangmasters (Licensing) Act, as it stands, protects temporary workers in the agricultural, horticultural and shellfish industries from exploitation by ensuring employment agencies are registered, and therefore regulated.

It was passed in 2004 after 23 Chinese cockle-pickers died in Morecambe Bay. The T&G union lobbied for the introduction of the original bill and now, as a section of Unite, it is concerned that illegal gangmasters have switched from agriculture to construction.

Harman is also leader of the Commons, which means she has responsibility for the timing and introduction of bills.

It has also emerged that the Institution of Civil engineers has set up a pan-industry steering group to address the issues surrounding migrants and other vulnerable workers in the construction industry.