The prosecution against Mr Dizaei failed

Iranian-born Superintendent Ali Dizaei was cleared at the Old Bailey in September after being subjected to years of Metropolitan Police investigations over claims of dishonesty and corruption.

The Police Complaints Authority (PCA) will supervise an inquiry into the conduct of officers involved in Operation Helios.

Scotland Yard said the inquiry, which will be carried out by another force, comes after complaints from the public about officers of various ranks.

Mr Dizaei has been suspended from his £52,000-a-year-job since 2001 and still faces disciplinary action.

The National Black Police Association has called for ethnic minorities to boycott the London police force over the failure to reach a deal to return Mr Dizaei to work.