A leading psychiatrist who hired a private investigator to spy on a beat officer he said should not be retired as medically disabled branded the policeman "corrupt" yesterday.

Consultant psychiatrist Dr Nicholas Cooling, aged 50, who helped set up the national police psychiatric service in May 2001, claimed it was his "duty as a citizen" to get hard evidence West Midlands Police constable Robert Millar was a "persistent malingerer".

Mr Millar had been with the force five years when he suffered a brain injury in a December 1998 car crash on duty.

Dr Cooling, then a psychiatrist with the force, hired an agent to watch the officer in March and May 2002, the General Medical Council was told.

Dr Cooling, who later worked at the Priory Hospital, Roehampton, as a visiting consultant, helped establish the national police psychiatric service which provides forces with proper medical legal opinions from psychiatrists with a knowledge of how forces operate.

He criss-crossed the country, working with various forces including West Midlands and Manchester, to set up the unit.

He told the GMC's fitnessto-practise panel in London: "He (Millar) was a persistent malingerer, married to a police officer and each of them were not acting in accordance with their oath. I felt we were dealing with two corrupt officers."

He believed Mr Millar's actions triggered by a desire for "very considerable material long-term gain", he told the tribunal.

Dr Cooling saw Mr Millar, then 29, three times in 2000 as he assessed his fitness to work.

He ruled Mr Millar had a mild brain concussion without demonstrable damage and was clinically depressed.

But he also felt the officer's dealings had been with a "distinct lack of candour", the tribunal heard.

Dr Cooling said: "I was very aware of my duty as a citizen because there was something very wrong with Millar's behaviour. He was exploiting illness, feigning illness for a long time and going for a personal injury award."

In July 2001 he ruled Mr Millar had a 37 per cent degree of disablement - a crucial decision which can affect the money he could be awarded.

By the time of the secret surveillance, Mr Millar had lodged a complaint in January 2002 against Dr Cooling with the GMC and an appeal with the Home Office about his award.

Mr Millar had also secretly taped the last of their three consultations in 2000, the panel was told.

Having gained tapes which showed Mr Millar going to the Post Office and newsagents, Dr Cooling sent them to West Midlands Police urging they be passed to its legal department.

They should be used as "crucial evidence" at the Home Office appeal and could help show Mr Millar was an "extremely aware individual", it was claimed.

Dr Cooling claimed within two months of working with the force in 2000 he was aware of a "level of quite shocking hostility" in the service to undermine his integrity with bogus complaints.

This came from officers or their federation of representatives who wanted sick leave, he suggested.

"I never had a GMC complaint before I worked for the force," he said. "There were officers being advised to complain to undermine my integrity - by their federation I assume."

Dr Cooling denied his fitness to practise was impaired.

The hearing continues.