The ruling means forces will have to delete images of anyone on their files who is innocent, unless they can show strong reasons why they are still needed to help combat crime.  It comes three years after the Court of Appeal ruled keeping photographs of law-abiding activists taken during protests breached human rights laws.

New rules banning the retention of the DNA of innocent people, except for those arrested for the most serious crimes, are also due to come in to effect next month. The latest ruling centred on challenges by two applicants, who can only be identified as RMC and FJ.

RMC is a 60-year-woman from Chelsea, who five years ago was arrested on suspicion of assault and had DNA samples, fingerprints and photographs taken. The Crown Prosecution Service decided not to charge her with assaulting a community support officer who had stopped her riding a cycle on a footpath, but the Metropolitan Police refused the "distressed" woman's request to destroy her records.

In the second case, FJ, a 12-year-old boy from Peckham, was arrested on suspicion of rape of his second cousin after voluntarily attending a police station for questioning in April 2009. No charges were brought after a third party witness did not confirm an offence had taken place.

The Met refused a request to destroy the material and also retained a record of his arrest and other information on the police national computer (PNC).

Lord Justice Richards, sitting at London's High Court with Mr Justice Kenneth Parker, said: "I am not satisfied that the existing (police) policy strikes a fair balance between the competing public and private interests and meets the requirements of proportionality.

"In my judgment, therefore, the retention of the claimants' photographs in application of the existing policy amounts to an unjustified interference with their right to respect for their private life and is in breach of Article 8 (of the human rights convention).”