Thirty construction firms including Sir Robert McAlpine Ltd and Balfour Beatty were ordered to disclose all emails and correspondence relating to blacklisting.
The High Court ruling came at the end of a two-day hearing which revealed that documents related to construction firms’ involvement with the Consulting Association blacklisting body had been destroyed.
The firms and four individuals will have to disclose relevant information by 12 February in addition to paying costs. The legal action has been supported by trade unions.
Unite director of legal services Howard Beckett said:
“Despite admitting their guilt, it is shameful the lengths that some of the construction firms involved in blacklisting have gone to cover up their involvement.
“It is only now after sustained legal action with the support of Unite that the lid is being lifted on a scandal which has ruined countless lives and led to hardship for many more.”