SHADY construction bosses were sent packing at the High Court yesterday when a judge threw out their bid to skip negotiations and pay blacklisted workers a pittance in compensation for years without employment.

Eight brass-necked firms, including Balfour Beatty, McAlpine and Carillion, even wanted the Information Commissioner to hand over the current home addresses of trade unionists and political activists they had systematically kept off building sites.

But Judge Master Leslie threw out their attempt to grab the private data.

He said company lawyers’ efforts to directly contact legally represented workers risked a breach of the Law Society code of conduct.

Union GMB accused the firms of using “secret and unorthodox” court applications in a bid to bypass unions and offer inadequate compensation.

GMB legal officer Maria Ludkin said: “The lawyers for the employers have used every trick in the book to trample on the legal rights of our members. 

“The judge has rightly dovetailed the operation of the compensations scheme into the outcome of the litigation.”

The eight construction companies, including Balfour Beatty, McAlpine and Carillion, maintained that their efforts were to help the people they had victimised.

They claimed in a joint statement that “without the High Court order, there is a risk that people will be denied the choice between the compensation scheme and the less certain court process.”

But trade unionists rubbished the low sums the firms had set aside — pointing out that the £15-20 million estimate made up less than 2 per cent of the eight companies’ combined profits.

Ms Ludkin said: “Legally represented blacklisted workers are likely to get a much better settlement through the courts,” branding the firms’ plan “a cheap underfunded PR stunt.”

Construction union Ucatt said that if the plans had gone ahead bosses could even have used the information to set up a new blacklist.

General secretary Steve Murphy said: “The blacklisters have no right to this information — it is the equivalent of a witness in a murder trial having their new identity given to the murderer.”

More than 3,200 names were found on a blacklist discovered five years ago during a raid on the Consulting Association by the Information Commissioner’s Office.

But only a tiny portion of documents were seized and the number of victims may run into thousands more.

In a separate case at the Court of Appeal yesterday ministers admitted that blacklisting had breached union activist Dave Smith’s human rights.

Business Secretary Vince Cable submitted a document conceding that construction giant Carillion had ridden roughshod over Mr Smith’s right to privacy and freedom of association under the European Convention on Human Rights.

But Mr Cable argued that Mr Smith was not entitled to compensation because he had been an agency worker.

It is the first time the government has intervened in the notable test case. 

Mr Smith said: “Blacklisted workers have always known that the illegal blacklisting was a breach of our human rights. 

“The fact that the UK government has admitted I was a victim of human rights abuse but is now going to fight against me in court is beyond belief.”