People often ask why trade associations (and others) do not create black lists of individuals and companies that make life difficult for them. A bill of potentially £600million being faced by construction company Sir Robert McAlpine provides an answer.

A group of construction workers say they were blacklisted by Sir Robert McAlpine via an organization called the Consulting Association.

The Consulting Association is said to have compiled a list of workers whose politics and union activity made them potentially disruptive. Sir Robert McAlpine and other contractors paid for the information to keep the workers off their sites.

Now 86 of the 3,400 people on the Consulting Association’s files have launched a High Court claim against Sir Robert McAlpine, claiming the company robbed them of their livelihoods.

The group, represented by Sir Hugh Tomlinson QC, the barrister involved in the News of the World phone hacking cases, alleges McAlpine had the worst record of blacklisting, which is why it is being targeted in the legal action.

The average claim is said to amount to about £200,000, so these 86 claims could cost Sir Robert McAlpine around £17million. If all 3,400 people on the Consulting Association list joined the action – and more are expected to become involved – it could potentially cost the company £600million or more.