The data protection watchdog has ordered four police forces to delete old criminal convictions from the Police National Computer (PNC).

The Information Commissioner's Office issued enforcement notices to Humberside, Northumbria, Staffordshire and West Midlands police forces after investigating complaints from four individuals. The ICO found that the old conviction information was held in breach of the principles of the Data Protection Act because it was no longer relevant and was excessive for policing purposes.

There has been increasing concern about the amount of data on individuals held by the police, focusing particularly on DNA samples. Last month, home office minister Meg Hillier told MPs she would welcome debate on the DNA database -- which now holds records of more than 4 million people -- after being quizzed on the case of an individual who had been wrongly arrested but could not get his DNA records removed.

Records examined by the ICO included a Humberside Police record relating to the theft of a packet of meat valued at 99p stolen by a child in 1984. The child was fined £15 at the time. West Midlands police hold a record of an attempted theft committed more than 25 years ago, where the offender was fined £25.

Staffordshire police hold records of a child aged under 14 who was cautioned by the police for a minor assault. The child was told the information would be deleted when she became 18. She has now been told that the record will not be deleted until she reaches 100 years of age.

Assistant information commissioner Mick Gorrill -- a former police officer -- said: "Each case relates to individuals who have been convicted or cautioned on one occasion and have not been convicted of any other offenses. Some of the incidents date back nearly 30 years. The offenses 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. I held the rank of detective superintendent in the police prior to my retirement after thirty years service. We are not satisfied that in these particular cases this information will be of any use for policing purposes."

All four police forces are appealing to the Information Tribunal against the ICO ruling, allowing them to retain the information until after the appeal is heard.