The high court case for unlawful conspiracy is against David Cochrane, Cullum McAlpine, Danny O’Sullivan and Stephen Quant, all four of whom undertook the role of chairman of the Consulting Association.

Mr McAlpine and Mr Cochrane were the first and last chairmen of the Consulting Association both of whom were employed by Sir Robert McAlpine. Mr O’Sullivan was employed by Kier and Mr Quant was an employee of Skanska UK.

The litigation is expected to force them to give evidence in court for the first time, the union said.

The action against the four leading blacklisters is part of a wider case being brought by Unite on behalf of over 70 construction workers who were blacklisted by the Consulting Association. These cases are for breach of privacy, defamation and for Data Protection Act offences.

As part of the legal action proceedings have also been issued against: 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 announced its latest round of legal cases ahead of the anti-blacklisting day of action and lobby of Parliament which will take place on Wednesday 6 December.

The union is calling for a full public inquiry into blacklisting, new laws to make blacklisting a criminal offence and the introduction of public procurement rules to bar companies found to have blacklisted workers from bidding for public sector contracts.

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.

“Since 2009 the individuals who were the controlling minds behind the systematic blacklisting of workers have sought to avoid taking responsibility for their actions. The workers who had their lives ruined deserve to see the leading blacklisters in court.

“Last year Unite successfully took high court action on behalf of hundreds of blacklisted construction workers and won millions of pounds of compensation for them. Unite is the only organisation which is continuing to take legal action on behalf of the victims of blacklisting.”

Unite assistant general secretary for construction, Gail Cartmail, added: “Unite will continue to lobby and campaign for justice for blacklisted workers until this disgraceful practice is ended once and for all.

“Unite is seeking justice for blacklisted workers through every avenue open to us whether that is legal, political or industrial.

“Whenever Unite uncovers blacklisting we will stamp out the practice and name and shame the guilty parties.”