A police decision to keep photographs of two crime suspects who were never charged has been declared a breach of human rights in a landmark High Court ruling.

Two judges have ruled the Metropolitan Police policy on custody photographs as "unlawful".

The ruling was won by two applicants referred to as RMC and FJ, who must not be identified for legal reasons.

RMC is a 60-year-old woman from Chelsea, who was arrested five years ago on suspicion of assault. She 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 cycling on a footpath, but the Met 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 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. During the arrest DNA was taken from FJ, along with photographs and fingerprints.

The Met refused a request to destroy the material and also retained a record of his arrest.

Today Lord Justice Richards 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 judgement, 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 European Convention on Human Rights."

Judges have ordered the Commissioner of the Met Police to pay the legal costs of RMC and FJ.

The Equality and Human Rights Commission, which intervened in the test case, said that the ruling meant the police "cannot keep photographs of people without criminal records or those not found guilty".

Unless the ruling is successfully appealed, the police are likely to have to destroy photographs held "of anyone who is innocent of any crime".