UP to 50 workers in the Hampshire area are on an illegal blacklist that prevented them from working in the construction industry, it has been revealed.

Three workers in Basingstoke are among those on the list that makes the county one of the hotbeds for what the Labour Party has branded a “national scandal”.

The High Court is hearing a £17million claim into an alleged “conspiracy to blacklist” 3,213 people from working on Britain’s major building projects.

Workers have had their livelihoods destroyed and reputations tarnished, Labour has protested – simply because they “raised health and safety concerns or were a member of a trade union”.

The Consulting Association – a firm funded by 20 construction companies – ran a database for the industry for 30 years.

Now the GMB union has obtained details of the 3,213 workers on the blacklist from the Information Commissioner’s Office (ICO).

It reveals that as well as the three people in the Basingstoke area, 22 on the blacklist lived in Southampton, and 24 others live elsewhere in Hampshire.

The GMB has only been able to contact around 200 people on the list, with the vast majority likely to be unaware that they were blacklisted.

The union has urged anyone who suspects they have been targeted to come forward so it can press for the release of files from the ICO – and win them compensation.

Paul Kenny, the GMB’s general secretary, said: “People have been deprived of an honest living through these illegal tactics which has blighted their families’ lives.

“They have been the victims of injustice over many years by multi-national companies, now seeking to live off public sector contracts.

“The GMB is calling on local councils not to award any new public work to the companies that operated the blacklist until they compensate those they damaged.”

Many more alleged victims of the blacklist – run between 1993 and 2009 – are expected to add their names to the High Court action.

The list was seized by the ICO in 2009, but it is only in the last year that the scale of the blacklisting has emerged – prompting a parliamentary inquiry.

Chuka Umunna, Labour’s business spokesman, said: “Workers have had their livelihoods destroyed just because they raised health and safety concerns.”