A man who kept an illegal database of information on construction workers has been found guilty of breaching the Data Protection Act (DPA) and had his case referred to the Crown Court for harsher sentencing than usual.

The Crown Court will be able to issue a sterner punishment than the maximum fine of £5,000 for breaching the DPA.

Ian Kerr, who ran the Consulting Association, kept a database of 3,213 workers’ personal details and trade union activities. Because he failed to register the database with the Information Commissioner’s Office (ICO), it is considered illegal.

After the hearing, the ICO made it clear it intended to move against those construction companies who used the information to vet employees.

The court case came after a raid by the ICO on Kerr’s offices in Droitwich, Worcestershire, in March. They found details on the workers that were being used by 40 companies to vet employment on their building sites.

The files included comments such as “Communist party”, “ex-shop steward, definite problems, no go”, “do not touch”, “orchestrated strike action” and “ lazy and a trouble stirrer”.

Kerr, who had been operating the files for 15 years, pleaded guilty.

Construction companies would pay an annual subscription of £3,000 plus quarterly charges for the information. Some were paying up to £20,000 a year.

Assistant Information Commissioner Mick Gorrill welcomed the prosecution.

“Ian Kerr colluded with construction firms for many years flouting the Data Protection Act and ignoring thousands of people’s privacy rights. Holding personal information on individuals without their knowledge, in these circumstances, is a serious breach of the Data Protection Act,” he said.