BLACKLISTED construction workers joined a picket outside a key inquiry hearing yesterday.

As the undercover policing inquiry prepared to hear pleas from the police for further delays, rank and file trade unionists called for the cover names of the spycops to be revealed.

In 2009 a secret blacklist of builders was exposed after a raid by the government’s Information Commissioner, implicating major firms including Kier, Costain, Balfour Beatty and Sir Robert McAlpine.

It is thought that some of the information in the files could only have been procured through collaboration between construction bosses and the police.

Activists argue that the publication of officers’ cover names, which were often identities stolen from dead children, will allow more victims of police spying to come forward.

Speaking outside the courts, Unite construction sector convener Darren Goldstone said: “We’re here to show our support for people who had their lives ruined by surveillance.”

Frank Smith, a blacklisted builder, added: “The officers’ cover names need to be revealed, along with the list of groups spied on, so the people who suffered can get some justice.”

One undercover officer, Mark Jenner, posed as a joiner and became a member of construction union Ucatt while deceiving a woman activist into a long-term relationship.

He was also active in the Building Workers Group, and last year the Star revealed that he had sought to gather information on deaths at work from unions and other campaigns.

It is thought he could have used this emotive issue as a way to ingratiate himself with other social justice campaigns.