If Victoria Police refuse to prosecute me over the death of Steve Guest, they must be asked why. If a law is "honoured more in the breach than the observance", then it is a bad law and needs to be changed, writes Rodney Syme.

The Victoria Police are "reopening the file" into the death of Steve Guest after I admitted last Monday week that I had provided him with the drug Nembutal.

Doctors have been easing or assisting (depending on your point of view) the deaths of their patients for at least the last 60 years, and probably for centuries.

They have done this because it is a necessity - dying can be associated with intolerable suffering that can only be relieved by death, and doctors have a fundamental ethical duty to relieve suffering.

In 1957, English judge Patrick Devlin created a precedent that has been adopted in principle in those countries which embrace legal systems derived from the British. He said:

If the first purpose of medicine, the restoration of health, can no longer be achieved, there is still much for the doctor to do, and he is entitled to [do] all that is proper and necessary to relieve pain and suffering even if measures he takes may incidentally shorten life.

Devlin was indicating that a doctor had a duty to provide treatment which the doctor could foresee would hasten death. But he also said that doctors had no special defence under the law compared to other citizens; yet any other citizen who could foresee the likelihood of death occurring from their action would be guilty of manslaughter.

The criminal law is solidly based around intention, and Devlin provided a legal precedent that the intention to relieve suffering justified unintentional (coincidental but foreseen) hastening of death.

Intention is a difficult concept to prove, particularly in medical matters. Devlin and the ambiguity around intentions allowed the introduction into palliative care in the late 1980s of 'terminal sedation', a practice of providing continuous analgesia and sedation to induce and maintain deep unconsciousness, without any provision of food or fluids, for terminal suffering that could not be relieved in any other way - "it provided a readily available means of controlling symptoms and overcoming distress where no feasible alternative existed previously".

Such treatment can clearly hasten death, and is validated by legal precedent and common medical practice, but not by law. The cumulative effect of injected analgesics and sedatives, plus dehydration, can cause death over a period of days, yet this is not considered an 'unnatural death' reportable to the coroner.

It is against this background that I saw and advised Steve Guest in 2005. He was terminally ill due to oesophageal cancer. He could not swallow, and despite a PEG stomach tube, he was starving to death, his nutrition consumed by the cancer.

His pain was somewhat relieved by morphine, but every time he had a dose he described it as like "a shot of lead into his brain". He was maintaining himself at home with the help of family, friends and an excellent GP, but was imminently facing incarceration in institutional care for the remainder of his life.

Steve had significant physical suffering, but even more intolerable was his psychological and existential suffering. He had a profound sense of loss of control over his life and of ending in an existence which was anathema to him.

He had a primal fear, felt by many dying people, which can consume the precious time around the end of life. Relief of this often unrecognised psychological and existential suffering is one of the most important palliative actions a doctor can take, and it is best achieved by giving that person control over the end of their life.

I discussed institutional palliative care and terminal sedation with Steve but he was adamant that it was not for him. I did advise and support Steve Guest in his terminal illness, and gave him medication (Nembutal) which was a remarkably effective palliation, as he gained the strength to advocate for law reform over the subsequent two weeks.

He apparently then used the medication to end his suffering and his life. Had he used a cocktail of the same drugs used in palliative sedation and taken them by mouth, the doctor prescribing those drugs would not have been in legal danger, able to argue that his intention was to palliate. I would similarly argue that my intention in providing Nembutal was to palliate Steve - it was not my intention that he should end his life. I could foresee this possibility but it was not my intention that he do so. It did prove to be his intention.

Over the past 20 years State Parliaments have rejected 16 Bills to protect doctors who provide such palliation in prescribed circumstances. Like other end-of-life interventions which may hasten death, the courts have ultimately been the avenue to changes in medical practice, as we have seen with abortion law reform.

Modern end-of-life medicine is based on judicial decisions and accepted medical practice rather than statute law. If Parliaments will not address the deficiencies in the law, then our courts must have an opportunity to influence the outcome, either by judicial precedent or jury decision.

Do I want to be charged? In a way, yes, because then a definitive decision could be made. But another part of me says no, because I wouldn't want the stress.

If I were charged, I'd be asking the jury to decide whether I'm a criminal or a good doctor. I'm pretty confident about what a jury would think.

Alternatively, if the Director of Public Prosecutions refuses to prosecute, he must be asked why. If a law is "honoured more in the breach than the observance", then it is a bad law and needs to be reviewed and changed. In Victoria, there is no better place for this than the Law Reform Commission for such an expert and independent review.

Dr Rodney Syme is a campaigner for voluntary euthanasia. View his full profile here.