ONE of the survivors in the case of Benjamin Geen has called for an independent investigation to discover why it took so long to discover there was a murderer working on the ward.

On Tuesday at Oxford Crown Court, Geen, 25, from Banbury, was convicted of murdering two patients and causing grievious bodily harm to a further 15 patients while working in the accident and emergency ward of The Horton Hospital, Banbury. Geen injected patients with a variety of drugs, which caused them to stop breathing, between December 2003 and February 2004.

During the trial the prosecution said that so-called unexplained respiratory arrests were very rare, but it was only after the case of Timothy Stubbs Geen's 17th and final victim that an investigation took place.

Robert Robinson, 55, of Oxford, who was Geen's third victim, has asked for an independent inquiry to find out how Geen was able to poison so many patients before suspicions were formally raised.

Mr Robinson said: "I certainly think an inquiry has got to be looked at. How was this guy able to get his hands on prescribed drugs for so long without other people knowing? He had already made comments to staff along the lines of 'it's amazing that every time I work, someone has a respiratory arrest'. Why did it then take so long for staff to investigate the matter further?"

Banbury MP Tony Baldry has backed Mr Robinson's call and said he is writing to Oxford Radcliffe Hospitals NHS Trust chief executive Trevor Campbell Davis.

Helen Pegg, spokesman for the Oxford Radcliffe Hospitals NHS Trust, said the trust would co-operate fully with any further investigation, but did not feel it was necessary. She said: "Our feedback from the police was that the investigation was very thorough and there was no way it could have been picked up any quicker."