© Photograph: Gareth Fuller/PAA road protester near Crowhurst, Sussex: over half of the UK's top construction firms are thought to have been involved in keeping a blacklist of environmental activists.
Hundreds of environmental activists were on a secret "blacklist" used by construction firms in an attempt to disrupt high-profile protests against road building and other developments.
Files on more than 200 campaigners were held alongside a list of more than 3,000 construction workers who had raised legitimate health and safety concerns or belonged to a trade union.
Last week MPs said the list had deprived thousands of people of work and driven some families to destitution. Evidence of the growing scale of the operation carried out by the Consulting Association has led to renewed calls for an official inquiry.
Chuka Umunna, the shadow business secretary, told the Guardian: "This is greatly concerning and we still don't know what the full scale of the blacklisting scandal was. In light of this new evidence, it is crucial that a full investigation of blacklisting commences."
During a debate on blacklisting in parliament last week, Umunna said more than half of the top 20 construction firms in the UK were involved.
