Most of the blacklisted construction workers barred from jobs at the Olympics site never even knew they were on a blacklist, it has emerged.

Those whose names were on a secret blacklist included workers living in postcodes E1 to E17 in the ‘host’ boroughs of Tower Hamlets, Newham, Hackney and Waltham Forest.

“These workers have been deprived of a living through illegal tactics which have blighted their families’ lives,” said GMB’s general secretary Paul Kenny. “They have been the victims of injustice over many years by multi-national companies living off public contracts.

“Not one company has yet been punished—nor paid compensation.”

They were blacklisted from the Olympics site because they were trade union or health and safety activists—but only 40 ever found out they were on the list. The union is now calling for compensation.

The scandal came to light in 2009 when the Information Commissioners Office raided the Consulting Association offices and seized its database of more than 3,000 names which was used by 44 companies to vet recruits.

But Commissioners never contacted the victims to let them know they were blacklisted, the union claims.