The ruling brings to 22 the number of convictions thrown out because of alleged misconduct by officers in an anti-gang unit in the Los Angeles Police Department.

However, LA District Attorney Gil Garcetti has warned that he will seek to have another 30 to 40 convictions overturned in the next few weeks.

They are some of several thousand potentially-suspect cases which investigators have started to re-examine in light of allegations made by a corrupt former officer.

Damaged reputation

The LAPD says it has already uncovered proof that its officers were involved in shootings, beatings, drug dealing, planting of evidence, false arrests, witness intimidation and perjury.

So far 20 officers have either resigned or been sacked or suspended as a result of the inquiry.

Los Angeles Police Chief Bernard Parks has already said he believes that at least three officers from the unit, known as Rampart Division, should face criminal charges.

The scandal is doing further damage to the reputation of a police department who many Americans most associate with the videotaped beating of black motorist Rodney King which led to the 1993 LA riots.

The current allegations follow disclosures made by a corrupt officer turned informant, Rafael Perez.

He was charged with stealing cocaine from a police evidence room and has implicated himself and other officers in numerous cases of misconduct in return for a lesser sentence.

These include a case in which he and a colleague shot an unarmed man and then planted a gun on him.

The two officers lied in court, saying the man had attacked them, and the accused was sentenced to 23 years in jail, although he has since been released.

Mr Perez was scheduled to be sentenced last month, but the hearing was delayed to give prosecutors extra time to interview him and uncover more possible corruption.

He has been given huge bundles of case files to review and has already identified 3,000 suspect convictions.

The latest overturned cases all involved drugs or weapons charges.

Of the 10 people, seven had served their sentences the other three were in custody.