Some of the biggest construction companies could have to pay out tens of millions of pounds in damages.
They made an “amended defence” of their role in blacklisting at London’s High Court last week.
The contractors involved are Balfour Beatty, Carillion, Costain, Kier, Laing O’Rourke, Sir Robert McAlpine, Skanska and Vinci.
The eight companies’ defence included “a full and unreserved apology” for their part in the “vetting of construction workers through the Economic League and The Consulting Association”.
The statement added, “We recognise and regret the impact it had on employment opportunities for those workers affected and for any distress and anxiety it caused to them and their families.”
The firms have admitted breaches of confidence and being part of an organisation that collected defamatory information against the workers.
The defamation admission means the companies cannot now claim “non-disclosure”, opening the door for further action from those seeking answers on how and why they were blacklisted.
The firms are still contesting the effect that it has had on the blacklisted people.
Blacklist Support Group secretary Dave Smith said, “The blacklisting wretches have run up the white flag.”
A safe victory for Sellafield strikers
Construction companies at Sellafield have granted the Unite union a senior shop steward on facility time to help workers with issues such as health and safety.
More than 1,200 workers employed by 14 sub-contractor companies are decommissioning or renewing nuclear facilities at the site.
They have taken part in industrial action, including strikes, to win the deal.
It also includes the creation of a health and safety committee.