The business secretary Vince Cable last week referred evidence of ongoing blacklisting of trade unionists at a major building project to the Information Commissioner’s Office.

This follows a recent report by the Scottish Affairs Select Committee which has been investigating historic allegations of blacklisting in the construction industry and which heard “clear evidence” from Unite the Union that the practice is still continuing. The committee chair wrote to the business secretary last week asking for a full investigation.

Unite says that blacklisting as a result of trade union activities has been going on within the contract for London’s Crossrail project run by BFK (BAM, Ferrovial and Kier). It welcomed the move by the business secretary but continues to call for a “full and proper Leveson style” inquiry.

The TUC has also backed calls from the committee to launch a formal investigation into claims of blacklisting on the project.

In its response to proposals put forward by the last Labour government on regulations outlawing the blacklisting of trade unionists in 2009, Thompsons said that legal sanctions needed to be introduced immediately. It warned against waiting for evidence of employers using these lists “as it would then be too late”.

Under the regulations, which were implemented in 2010 by Labour, it is now unlawful to make or use a blacklist or to refuse employment or subject an employee to a detriment because they are on a blacklist.

Victoria Phillips of Thompsons solicitors said: “An investigation into blacklisting is one thing, but it’s clear that the existing regulations do not go nearly far enough in terms of providing effective legal protection and remedies, as the events at Crossrail clearly demonstrate. We now need legislation that makes blacklisting a criminal offence so that trade unionists can exercise their legitimate rights without fear of losing their livelihood.”

Read the Thompsons response to the 2009 draft regulations consultation