Dr Dave Moor, a GP in Newcastle-upon-Tyne, was questioned for more than seven hours at a local police station after arriving voluntarily to make a statement. Shortly after 6pm last night, a spokesman for Northumbria Police said that Dr Moor had been released.
He had been questioned about the death of a former ambulanceman, George Liddell, who had cancer of the colon and died while in his care.
The Newcastle coroner, Leonard Coyle, has halted Mr Liddell's funeral and withdrawn permission for the body to be released, pending a police investigation. A health authority inquiry into Dr Moor's conduct was also put on hold last Friday, pending the police investigation.
Dr Moor spoke out on euthanasia after a retired GP, Dr Michael Irwin, a former adviser to the United Nations, admitted helping 50 patients to die during his career.
Dr Moor, who claims to have helped 150 people to die said last week: "In almost 30 years I have probably helped four or five people every year to die. I have no problem with it morally or ethically and quite frankly I couldn't give a damn what the law says. My conscience is clear as the majority of the people I help to die are terminally ill, it is simply speeding up the inevitable in a humane way."
Dr Moor had earlier said he was willing to co-operate with the police because he had "nothing to hide".
Both Dr Irwin and Dr Moor defended their actions in prescribing lethal doses of painkilling drugs to the patients, on the basis of the principle of double effect.
That principle states that it is permissible to administer drugs without limit to terminally ill patients, even though they may shorten their lives, provided the intention is to relieve suffering and not to end life.
Support among the public for euthanasia has been rising steadily. The latest British Social Attitudes survey, for 1996, indicated that 82 per cent of the public would back it in certain circumstances, up from 50 per cent in the early 1950s. And a leading article in the Lancet last year said doctors' leaders were out of touch and were failing to recognise growing disquiet among the public over what happens at the end of life. Glenda CooperReuse content