The action is part of a wider case being brought by Unite on behalf of over 70 construction workers who were blacklisted by the Consulting Association.

The latest cases are for breach of privacy, defamation and for Data Protection Act offences.

The union is also taking action against a host of major contractors.

They are Sir Robert McAlpine Ltd, Skanska UK Plc, Laing Limited, John Laing Construction Ltd, Kier Ltd, Balfour Beatty Kilpatrick Ltd, Balfour Beatty Construction Ltd, Crown House Technologies Ltd, Costain Building & Civil Engineering Ltd, Costain Ltd, Costain Oil Gas & Process Ltd and Carillion Construction Ltd.

Unite has already taken High Court action against the companies involved in the Consulting Association.

The initial court action was completed in 2016 and resulted in hundreds of workers receiving millions of pounds in compensation.

Unite assistant general secretary for legal affairs Howard Beckett said: “Unite is determined to ensure that the people directly responsible for blacklisting workers and ruining their lives are brought to justice and have to answer for their actions.”

A Statement from Sir Robert McAlpine said: “There is no blacklisting at Sir Robert McAlpine. We have a zero-tolerance policy towards blacklisting, illegal or unfair recruitment practices and we expect all our sub-contractors to comply with this.

^“We were a founding member of The Construction Workers Compensation Scheme which was established to provide affected workers with easy access to compensation and, despite this being an industry-wide problem, we were one of only eight companies that apologised and paid financial settlements to workers through the High Court.”