Tens of thousands of criminal records could be deleted after a landmark ruling that police were breaking rules on the holding of personal details.

Police reacted with dismay to a judgment by the Information Tribunal, which could force them to review millions of records of minor crimes.

The ruling opens the way for all those who have been convicted of a minor offence when young, and who have since remained out of trouble, to apply for their record to be removed from the Police National Computer.

Police privately cautioned last night that there were potentially much wider implications. “A crime may look very trivial, but it might still be of significance to a person’s potential behaviour,” a police source said.

They also said that the ruling might put an end to the wider collection of data, brought in after the murders of Holly Wells and Jessica Chapman in Soham, Cambridgeshire, which was designed to increase the chances of catching criminals.

In a second blow to the storage of crime records, the Ethics Group, a government-appointed advisory body, gave warning that keeping DNA samples of people arrested but never charged or convicted is a potential breach of human rights laws.

Yesterday’s tribunal ruling ordered five police forces to delete the criminal records of five individuals from the national computer, which holds details of millions of people convicted, cautioned or reprimanded for a crime.

Under present police policy, an individual’s criminal record remains on the computer for 100 years.

The forces had appealed against a ruling by the Information Commissioner that they remove information about minor crimes because storing it breached data protection laws. Mick Gorrill, assistant commissioner at the Information Commissioner’s Office, said: “We welcome the ruling, which upholds our view that there is no justification for this old conviction data to be held by the police.

“We believe that this is a landmark ruling which will have wider implications for police forces around the country and will ensure that irrelevant details of old criminal convictions are deleted. Those concerned were caused harm and distress by the retention of this data.”

The five cases, some of which dated back almost 30 years, involved the police forces of Staffordshire, Greater Manchester, West Midlands, Humberside and Northumbria.

One case involved Kylie Smith, now aged 20, who complained because she said that a conviction for common assault had obstructed her ambition to become a carer. Ms Smith was reprimanded in 2001 when she was 13 and her background was disclosed by Staffordshire Police during a criminal records check when she applied for a job.

Another case related to a record kept by Humberside Police about a person convicted at the age of 16 of stealing a packet of meat worth 99p in 1984. The person, who has not been identified, was fined £15.

A third case involved someone convicted in 1978 at the age of 15 of two offences of attempted theft for which he received a conditional discharge and an offence of criminal damage for which he was fined £25 and ordered to pay £6.60 compensation.

He had inserted metal blanks into an amusement arcade roulette machine which years later he considered to be a “juvenile prank”.

The tribunal ruled that in each of the cases the conviction information was irrelevant and excessive for the purposes for which it was held and had been retained for longer than necessary. The judgment said that although the tribunal was not drawing up general rules, the decision would inform the future approach of both the police and Information Commissioner to storing criminal convictions.

Ian Readhead, deputy chief constable of Hampshire and spokesman on data protection and freedom of information for the Association of Chief Police Officers, said: “We are very disappointed with the decision of the Information Tribunal, which could have far-reaching implications for the police service as a whole. The Bichard inquiry which followed the tragedy of the Soham murders recommended that forces should reconsider the way in which records are managed. It is now important that clear national guidelines are put in place so that forces take a consistent approach to the retention of criminal records.”

The police can appeal against yesterday’s judgment. Mr Readhead said: “We will now take some time to discuss these implications with the service and decide on the most appropriate course of action.”

Times Recommends

• Should Knox’s trial even have reached the courtroom?
• All that glitters is not sold in Wright’s world
• Believe it or not, Big Brother is your friend