Union leaders in Scotland repeated calls yesterday for a public inquiry into “disgraceful” blacklisting and demanded compensation for those affected by the practice.

Dundee Trades Union Council secretary Mike Arnott told Congress delegates yesterday it had given him “no slight amount of displeasure” to see construction firm Sir Robert McAlpine carrying out his hometown’s waterfront development — embroiled as it is in a high court case at the centre of the blacklisting affair.

The firm admitted in November that it had used its lists to “keep an eye” on individuals but denies that the data legally constituted a blacklist.

Mr Arnott said: “If our movement stands for anything it stands for unity between the employed and unemployed.”

Meanwhile Unite delegate Scott Walker repeated calls for a full public inquiry into the “abhorrent and disgraceful” practice, as opposed to MPs’ and MSPs’ own limited investigations.

Meanwhile victims had yet to see compensation and payouts were rumoured to be as little as £1,000 a head.

“Until five years ago, these workers didn’t know they were on a list, they just knew they couldn’t get work.

“How can offering such a pittance in compensation in any way make up for years of unemployment and distress?” he said.s

The unions’ long-held suspicions were confirmed in 2009 when investigators raided the Consulting Association’s offices, retrieving a database of 3,200 would-be construction workers and 44 clients including Amec, Amey, Balfour Beatty, Bam Nuttall, Carillion and Morrison.

The conspiracy took on even greater dimensions in 2012 when the Information Commissioner’s Office testified that some entries “could only have been supplied by the police or the security services.”