A RETIRED GP accused of killing three of his patients will not give evidence in his trial.

Dr Howard Martin's defence started yesterday, but he will not be going into the witness box.

The first defence witness was Home Office pathologist Dr Nathaniel Carey, who gave evidence for 25 minutes during the afternoon session.

Other experts will be called by the defence team, along with character witnesses for the 71-year-old former County Durham doctor.

Dr Carey told the court he had worked on some of the country's most high-profile cases, including the Soham murders and the London July 7 bombings.

The pathologist carried out a second post-mortem examination on Mr Moss and said he found a 4in tumour on his lung, which was "certainly very serious, indeed".

Earlier, the prosecution case came to an end with Dr John Grenville telling the jury that morphine toxicity played a part in the deaths of all three of Dr Martin's patients.

Dr Martin, now of Gwynedd, North Wales, denies killing Harry Gittins, 74, from Newton Aycliffe, Frank Moss, 59, from Eldon, near Bishop Auckland, and Stanley Weldon, 74, from Coundon Grange, all County Durham.

The jury, at Teesside Crown Court, has heard that the three men received large doses of morphine from Dr Martin in the hours before they died.

Dr Grenville, secretary of the Derbyshire Local Medical Committee, was asked by Robert Smith QC, prosecuting: "Do you consider that it did hasten their deaths?"

Dr Grenville said that he did.

Mr Gittens, who had throat cancer, had received chemotherapy and radiotherapy.

During three visits by Dr Martin, he was given a cocktail of injections of morphine, diamorphine and chlorpronazine on January 21, last year, and died the following day.

Mr Moss, who had lung cancer, was given high doses of morphine throughout March 13, 2003, and died the following day.

Mr Weldon, who had Alzheimer's disease, died on March 18, 2003, after being given morphine following a stroke.

Dr Grenville told the jury: "He died a matter of hours - I think a maximum of five hours - after being given a dose of morphine which was, in my view, far in excess of what his symptoms called for, and a dose I would not allow anybody to give to me in full-health for fear of death."

The case for the defence will continue today.