A football fan who alleges that he was the victim of a serious assault by police has succeeded in blocking the retirement of one of the accused officers pending a legal challenge.
The Metropolitan Police inspector, who could face disciplinary proceedings for gross misconduct, was stopped from retiring just hours before he was due to quit.
Once he leaves the force, disciplinary action can no longer be taken against him under police rules.
A High Court judge said the inspector, who is also facing criminal proceedings, should not be allowed to retire until his alleged victim "Mr A" has had a chance to bring a legal challenge against a Met decision allowing him to quit.
Heather Williams QC, appearing for Mr A, said: "There is considerable public concern that in the past officers have been able to avoid the disciplinary process by way of retirement."
Ms Williams argued that Article 3 of the European Convention on Human Rights, which prohibits torture or inhuman and degrading treatment, might require a disciplinary hearing to be held to ensure "an effective investigation" into the serious allegations made against the inspector and two other police officers.
Lawyers for the Met and the inspector argued he was already facing an effective investigation in the form of a criminal trial. Disciplinary proceedings were therefore unnecessary and there was no good reason to stop him retiring.
The court heard the inspector was charged with assault occasioning actual bodily harm, attempted ABH and perverting the course of justice.
Mr Justice Wilkie ruled there was an arguable case that, in the event of an unsatisfactory trial, disciplinary proceedings might also be necessary to comply with Article 3 and the case against the Met should go to a full judicial review hearing.
The judge said: "In my experience many odd little things can happen in the course of the criminal process which can result in a prosecution coming to an abrupt end without findings of fact, without any attribution of responsibility."
Mr A's solicitor, Tony Murphy of Bhatt Murphy, said later: "Officers should not be allowed to evade accountability by retiring whilst under investigation.
"My client was deeply affected by how he was treated by this inspector. He hopes that his case will clarify the law and protect other members of the public."
The case arose after Met deputy assistant commissioner Fiona Taylor decided in October not to suspend the inspector from duty.
Police officers cannot retire while suspended and the move would have ensured that the inspector would have remained subject to misconduct proceedings.
Ms Williams told the court that the Independent Police Complaints Commission (IPCC) had made it clear that it considered the public interest required suspension to take place as the inspector and the two other officers had a case to answer for gross misconduct in respect of the use of force on Mr A.