MINISTERS should order a public inquiry into police collusion with construction industry blacklisting, trade unionists demanded yesterday, as new evidence related to the 30-year scandal emerged.

The official undercover policing inquiry recently disclosed that one former officer with the cover name “Dick Epps,” who spied on left-wing campaigns from 1969-1972, went on to work in the Metropolitan Police’s industrial intelligence section.

A government raid in 2009 revealed that thousands of construction workers had been blacklisted by a cartel of Britain’s largest building firms for their trade union activities.

Some of those workers are now “core participants” in the police spying inquiry, after it emerged that intelligence on their blacklist files could only have been supplied by the police.

But campaigners have argued that the blacklisting operation merits an additional inquiry, citing evidence that the practice is still ongoing on major building sites.

Unite assistant general secretary Gail Cartmail said: “Once again we have unearthed more links between the police and those involved in blacklisting.

“It’s clear there was direct collusion between the police and the blacklisters who ruined workers lives, but it is going to be impossible to find out the full extent of that collusion and who knew about it until there is a full public inquiry into blacklisting.”

In the interim, she said it was “essential” that the undercover policing inquiry opens up its books. Victims of police spying have complained that information is not being disclosed, giving the police an unfair advantage in determining the inquiry’s focus and pace.

“It would be simply intolerable if SDS officers are allowed to remain in the shadows and escape having to answer for their actions,” Ms Cartmail added.