"There is information on the Consulting Association files that I believe could only be supplied by the police or the security services"
He also told the court that the Consulting Association held information on elected politicians, journalists, lawyers and academics.
Dave Clancy is the Head of the Investigations Team at the Information Commissioners Office, the man who led the raid on the Consulting Association premises and discovered the blacklist. He is an ex-police officer.
Labour MP John McDonnell said after hearing these revelations: