The Information Commissioner's Office (ICO) has ordered four police forces to delete old criminal convictions from the Police National Computer.

The ICO is concerned that old conviction information is held contrary to the principles of the Data Protection Act because the information is no longer relevant and is "excessive for policing purposes".

Personal data processed for any purpose should be adequate, relevant and not excessive, and should not be kept for longer than is necessary for that purpose.

The ICO issued Enforcement Notices to Humberside, Northumbria, Staffordshire and West Midlands Police after investigating complaints from four individuals.

The police forces have referred each case to the Information Tribunal, which means that the information in question does not need to be deleted until after the appeal is determined.

Mick Gorrill, assistant commissioner for the ICO, said: "Each case relates to individuals who have been convicted or cautioned on one occasion and have not been convicted of any other offences.

"Some of the incidents date back nearly 30 years. The offences were non-custodial and we believe there is no justification in terms of policing purposes for retaining the information.

"The retention of the previous conviction information is causing harm and distress to the individuals concerned. We are not satisfied that in these particular cases this information will be of any use for policing purposes."

The conviction information includes the following:

The police forces concerned refused to comment because appeals are in progress.