Serious flaws in the care of a psychiatric patient with a history of violence allowed him to escape from hospital and kill a man, a report said today.

The 2004 killing of Denis Finnegan in Richmond Park, south London, by paranoid schizophrenic John Barrett could have been avoided by better care, according to an independent inquiry.

The report said the quality of care provided to 43-year-old Barrett by Springfield hospital in Tooting, south London, fell short in "a number of areas".

Staff failed to monitor him sufficiently and placed too much emphasis on his wishes rather than public safety, despite the fact he had previously stabbed three people in the outpatients department of St George's hospital, also in Tooting, in 2002.

The inquiry condemned as "seriously flawed" the decision by consultant psychiatrist Dr Gill Mezey to give Barrett an hour's "ground leave" from the Shaftesbury Clinic, a secure unit at Springfield, which allowed him to escape.

After buying several kitchen knives, Barrett took a taxi to Richmond Park and repeatedly stabbed 50-year-old Mr Finnegan, who was on his morning cycle ride.

Barrett said afterwards that he had bought the knives because voices in his head were commanding him to kill.

He pleaded guilty to manslaughter, was sentenced to life imprisonment in March last year and is currently being treated at Broadmoor hospital.

The inquiry, commissioned by the South West London Strategic Health Authority, said: "We do not say it was predictable that John Barrett would experience command hallucinations telling him to kill, but the risk of serious violence associated with deterioration in his mental state was known.

"We conclude that one of the factors that contributed to the killing of Denis Finnegan was that John Barrett's illness was inadequately treated."

The inquiry also questioned whether the Shaftesbury Clinic should remain open as a secure unit.