The Director of Public Prosecutions for England and Wales, where assisted suicide is a statutory offence, said that relatives of people who kill themselves will not face prosecution as long as they do not maliciously encourage them and assist only a "clear, settled and informed wish" to commit suicide.

Lord Advocate Elish Angiolini said there was no need for such guidelines in Scotland, where there is no offence of assisted suicide, but helping another person to end their life may amount to homicide depending on the circumstances of the case.

Her comments were welcomed by Independent MSP Margo MacDonald, who said that legislation was the only proper way in which to clarify the issue. But Jeremy Purvis, Liberal Democrat MSP, said that the lack of guidance north of the border was "deeply regrettable".

He said: "The proposed guidance that they are consulting on in England is very helpful. It is specific. It is also sympathetic and tolerant. I agree that the focus has to be on changing the law but the guidance that is being consulted on does move the debate forward. Unfortunately it is the reverse in Scotland, which is deeply disappointing.

"The position of the Lord Advocate sets Scotland back with regards to people in very difficult situations knowing how prosecutors will operate and what specific issues they will take into account, especially when that kind of clarity is now being provided south of the border."

Keir Starmer, Director of Public Prosecutions, issued his guidance after the Law Lords backed multiple sclerosis sufferer

Debbie Purdy’s call for a policy statement on whether people who help someone commit suicide should be prosecuted.

He outlined 16 "public interest factors" that would result in someone who helps their relative to end their life facing prosecution and 13 factors against taking legal action.

Mr Starmer said: "There are no guarantees against prosecution and it is my job to ensure the most vulnerable people are protected while at the same time giving enough information to those people like Ms Purdy who want to be able to make informed decisions about what actions they may choose to take."

In a letter sent to Mr Purvis, who had asked Ms Angiolini for clarification on the issue north of the border, the Lord Advocate wrote: "It is important to recognise the different legal landscape in Scotland, where involvement in a suicide might amount to homicide, as well as a different system of public prosecution.

"My position, however, remains that it would be inappropriate in the Scottish context to prepare and publish detailed prosecution guidance in this area."

Ms MacDonald, whose bill on physician-assisted suicide is expected to come before the parliament within the next two months, said the guidelines issued by Mr Starmer may have "confused the issue" in England and she agreed with Ms Angiolini that there was no need for further information to be published in Scotland.

She said: "It is perfectly plain [in Scotland] that the fiscal service will decide after there has been a proper investigation of all the facts whether or not it will be in the public interest to prosecute."

Ms MacDonald said that the focus should be on legislation that would consider the role of doctors, rather than family members, in helping someone to end their life.

She said: "I want to properly examine the whole thing. That would mean people would not go to take advantage of Swiss laws and we would have our own laws worked out in terms of what we think is right and fits in with our attitudes."