UNITE the union is taking fresh legal action to see that construction companies which blacklisted thousands of people are “finally forced to account” for their actions.

The union said today that it would be taking a case to the High Court on behalf of workers whose names were found on a list drawn up by the Consulting Association.

The Association was long suspected of being funded by construction firms to maintain lists of trade union activists.

Following a 2008 investigation into a spate of dismissals of construction workers at the Manchester Royal Infirmary that were deemed suspicious, the Association’s offices were raided the following year.

Documents discovered at the premises showed that the Association had created a list of at least 3,213 people.

The list contained the names of workers who were considered to be “trade unionists,” “militants,” or “troublemakers” by various firms.

It also described the political views of many workers, as well as their private lives and their family situations.

The document had then been resold or passed on to more than 40 major construction businesses, including Carillion and Willmott Dixon.

In May 2016 a joint court case by the GMB, Ucatt and Unite unions successfully proved that at least 256 workers had financially and personally suffered as a result of blacklisting, and that their rights of privacy and confidentiality had been breached.

The workers who had gone to court were awarded over £10 million in compensation.

Following this landmark case major trade unions have repeatedly taken construction companies to court, earning considerable amounts of compensation.

However, they say the figure of 3,213 people represents barely 5 per cent of those who were victimised by employers — and that up to 60,000 workers may have potentially faced victimisation.

A court case in March last year also confirmed widespread allegations that police and Special Branch officers were involved in both infiltrating trade unions and providing details for the blacklists.

The details of this latest case are yet to be revealed, but it is understood that Unite will be pursuing top construction industry bosses whom it believes were complicit in blacklisting but avoided accountability for their actions.

Unite assistant general secretary Howard Beckett said: “Unite is totally committed to ensuring that the key individuals behind blacklisting workers are required to account for their crimes in the public arena of a court.

“This is the minimum that the affected workers deserve. They need to see those responsible in the dock and finally forced to account for their actions.

“The forthcoming court case will finally ensure this will happen.”

Unite assistant general secretary Gail Cartmail added: “There remain employers in construction and other industries who continue to believe it is somehow acceptable to engage in the disgusting and deceitful practice of blacklisting, to ruin people’s lives.

“We are seeing blacklisting ‘outsourced’ to labour suppliers at the beck and call of large firms and acting as unaccountable instigators of union busting.

“That’s why Unite is still fighting for justice for those who were previously affected, but is also fighting to stamp out contemporary blacklisting.”

The court action is set to begin in June.