A LAW that would legalise assisted suicide should be tightened up to protect patients who wish to end their lives as well as those who help them to kill themselves, legal experts have said.

MSPs met yesterday to hear evidence on the controversial Assisted Suicide (Scotland) Bill, which if passed, would give those with degenerative or terminal conditions the right to commit suicide by taking a fatal dose of a drug prescribed by a GP.

Lawyers and police warned that if the law was passed in its current form, people who act in good faith could find themselves prosecuted for homicide due to a lack of clarity of what it meant to help someone end their life.

Meanwhile, doctors' representatives said that medical professionals must not be forced to help their patients kill themselves, if they were morally opposed to it.

Under the proposals, patients wishing to end their life would have to make three separate declarations to doctors, with set time delays including a 14-day "cooling off" period.

Doctors would then supply a licensed facilitator, who would oversee the process and have no relationship with the patient, and write a prescription to enable assisted suicide to take place. It is envisaged that a loved one or the facilitator would assist the person who wished to end their life, although the patient would have to self-administer the drug.

However, concerns were raised to MSPs on Holyrood's Health Committee that definitions included in the Bill were unclear. Professor Alison Britton of the Law Society of Scotland said: "We need to be very clear what actually this assistance encompasses and we need to be also clear at what point is there a demarcation where assistance is being given and that actually crosses over to being complicit in homicide."

Stephen McGowan, representing the Crown Office and Procurator Fiscal Service, said there was a "fine line" between assisting suicide and taking someone's life.

"The key part of this is there is no definition of what assistance actually is and what it is to assist someone in suicide. It is probably something that should be looked at... otherwise it does expose those who might seek to assist others to criminal prosecution, which is obviously not desirable."

The Bill was introduced by the late MSP Margo Macdonald, and has been taken over by Green MSP Patrick Harvie following her death in April last year. A previous bid to legalise assisted suicide was defeated in 2010, however, supporters of the Bill insist public opinion has shifted dramatically since then.

The Scottish Government does not support the proposals, however, MSPs are likely to be allowed a free vote on the issue.

Dr Francis Dunn, president of the Royal College of Physicians and Surgeons of Glasgow, said having the option of discussing assisted suicide with patients was, to some doctors, "an alien concept" and the majority view of his organisation was that it "impinges" on the trust relationship between doctor and patient.

"It would be very important I think, if this were to proceed, to have a conscience clause," he said. "One would be concerned about the patient having to go to different doctors to find one that was in agreement with it (assisted suicide).

"But I think the conscience clause is very important and it is also important to emphasise that there are diverse views within the profession."