'I'm a trade unionist, not a terrorist'
Dave Smith was one of hundreds of workers in the construction industry put on a 'blacklist' due to their trade union activities.
He says it destroyed his career by preventing him from getting and maintaining work.
The police has admitted it supplied information to the blacklist, from officers spying on workers.
The Victoria Derbyshire programme has found police have known for two years which workers were targeted but have not told them.
Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News Channel.