Delegates call for blacklisting action

They also want a Leveson-style public inquiry and changes to the law so that blacklisting carries a prison sentence and unlimited fines for damages.

GMB's Justin Bowden proposed the motion, saying that 3,200 names were found in the 2009 Information Commissioner's Office raid which exposed the involvement of companies including Carillion, Balfour Beatty and Mowlem.

He said the people named were only doing their duty, usually as health and safety reps calling attention to serious problems and organising union rights.

The firms involved should not get any more public work until they apologised and gave compensation, he said.

The culture of blacklisting read like "a low-budget spy film script," Unite assistant general secretary Gail Cartmail said.

"Unite supports the call for a day of action to expose the hideous abuses by rogue bosses. It is a disgrace that needs to be eradicated."

Ms Cartmail showed delegates a packet of unredacted files that had come into the union's possession from the blacklisting organisation, the Consulting Association, following the 2009 bust.

She said: "These are just a handful of files, but each name is a person - a family, a life ruined.

"The contents read like a low-budget spy film script, using codes and cross references. We had to write to the members named to tell them they are blacklisted - this cannot be right. We want full disclosure."

Last week, Unite gave evidence to the Commons Scotland committee's blacklisting inquiry and asked for it to investigate the case of one of the stewards working at Grangemouth for BBES.

The union said that he was selected for redundancy by the man who was "the spy in chief" for the company.

Although this steward will be back at work thanks to action by Unite members, Ms Cartmail called the case "just the tip of an iceberg."