Thousands of workers in the construction industry were denied employment because of a secret "blacklist", a court heard today.
Ian Kerr built up a database of 3,213 people which included highly sensitive and personal information as well as trade union links and employment history, Cheshire magistrates were told.
He then offered the information to construction firms to vet potential employees.
Kerr's organisation, the Consulting Association, in Droitwich, West Midlands, was raided by the Information Commissioner's Office (ICO) last March and he was charged with a breach of the Data Protection Act.
Kerr, 66, of Avoncroft Road, Stoke Heath, Worcestershire, did not attend Macclesfield Magistrates' Court today but entered a guilty plea through his solicitor.
Amina Khan, prosecuting for the ICO, told the court Kerr charged firms an annual fee of £3,000 to subscribe to the service and £2.20 to access the details of named individuals.
She said: "He collated and provided information to construction companies in relation to individuals that were working for them or seeking employment."
The ICO says it believes Kerr ran the blacklist for up to 15 years.
It has named around 40 companies which were subscribers to the database, including Amec Construction, Balfour Beatty and Morgan Est.
James Strong, defending, said Kerr was just a salaried employee of the organisation, which he described as a trade association.
Since the ICO raid the Consulting Association was ordered to cease operations and Kerr has lost his £48,000-a-year job, Mr Strong said.
Adrian Long, chairman of the magistrates, said it was unclear who profited from the Consulting Association's activities and adjourned the case for the ICO to undertake further investigations.
He said: "We need to know the nature of this organisation and exactly what sums of money were involved.
"Was (Kerr) simply an employee and others were financing the organisation and taking the money?"
Mr Long ordered the ICO to establish the "structure, ownership and finances" of the Consulting Association.
Outside court, electrician Steve Acheson, 55, from Denton, Manchester, said he had been denied work for four out of the last six years because of Kerr's blacklist.
He said: "I was unfairly dismissed in 2000 and later won an industrial tribunal against that company.
"Because of that information being on Kerr's blacklist, few companies would employ me.
"To be out of work for such a long time, it affected my health and my family.
"My life was devastated. I couldn't understand why nobody would employ me.
"There was no recession then. I am a highly qualified and experienced electrician and I work hard.
"But nobody would take me on because of this blacklist.
"It makes me very angry that for many years Kerr was earning a living denying others the right to do the same."
Mick Gorrell, Assistant Information Commissioner, said he was pleased with Kerr's guilty plea and pledged enforcement action against the companies who subscribed to the blacklist.
He said: "This was a flagrant abuse of people's rights.
"It was a covert database which meant that those who featured in it were unaware of its existence and unable to view or challenge the content, its accuracy or fairness.
"Many people will have been left without a job and with no idea why.
"We will be looking at the companies which subscribed to the database and consider sending enforcement notices."