Were police at centre of blacklists?

The investigation by the Force's Directorate of Professional Standards' (DPS), which is to be supervised by the Independent Police Complaints Commission, follows mounting evidence that both the police and the security forces may have provided information for a blacklist run by the Consulting Association.

The issue first came to light in January 2012 when Information Commissioner's Office head of investigations David Clancy - who led a raid on the association's offices in 2009 which discovered a database with details of thousands of individuals - told an employment tribunal that "information on some of the blacklist files could only have come from the police or the security services."

Mr Clancy repeated the assertion in evidence to the Scottish affairs select committee investigation into blacklisting. 

The claims of collusion are to be probed as part of Operation Herne, an ongoing investigation into the activities of the Special Demonstration Squad, a deep undercover section of Special Branch.

The investigation has been set up as a result of a complaint by the Blacklist Support Group.

The Met DPS originally refused to investigate the complaint, but was forced into a U-turn after a successful appeal to the Independent Police Complaints Commission (IPCC) by solicitors Christian Khan.

Partner at Christian Khan Sarah McSherry said the IPCC's decision to uphold the appeal was in stark contrast to the original DPS view that "the complaints process is not the correct vehicle to forward their concerns or allegations."

She said they would be making further representations to the IPCC arguing that, "given the seriousness of the allegations of widespread corruption and criminal behaviour on the part of Metropolitan Police officers, the DPS should have no involvement in the investigation of this complaint."

Dave Smith of the Blacklist Support Group added: "We want to know why information collected by the police has ended up on a secret blacklist of trade unionists operated by multinational companies.

"If police collusion is proven, at best it is individual corruption. At worst it is systematic state involvement in a major human rights conspiracy."

Ucatt construction union general secretary Steve Murphy said the decision was a major step forward.

"As more evidence emerges about the extent of the state's involvement in blacklisting construction workers, it is essential that this investigation is followed by a full public inquiry into the vile and disgusting practice of blacklisting.

"Those whose lives were ruined must be given the full facts," he said.

Unite assistant general secretary Gail Cartmail called for "a full and transparent investigation, backed by statutory powers, into all the allegations associated with the sordid spying enterprise called the Consulting Association."