The Government has been urged to launch a probe into claims of blacklisting against workers on the prestigious Crossrail project after "clear proof" the practice is continuing.

The chairman of the ­Scottish Affairs Select Committee has written to Business Secretary Vince Cable calling for a full and thorough investigation.

The committee has been taking evidence from the building trade, including unions, as part of an inquiry into blacklisting and had now heard "compelling evidence" it was used in the £14.5 billion project to build a 73-mile railway through Central London.

Labour MP Ian Davidson, who chairs the committee, said Mr Cable indicated during a Commons debate this year that he is willing to look at any evidence that indicates blacklisting of construction workers is continuing.

Mr Davidson said Gail Cartmail of the Unite union had given the committee "what we believe to be clear proof" that the activity was going on within the contract for the project.

He added: "We intend to continue our wider investigations into blacklisting and will be calling further witnesses.

"However, we believe that the Government should now investigate, as promised, the clear and unequivocal evidence that has been received about blacklisting on the Crossrail project."

Blacklisting came to light four years ago when the West Midlands offices of the Consulting Association were raided by the Information Commissioner's Office and a list of thousands of ­construction workers was seized.