MSPs will be allowed a free vote on proposals to legalise assisted suicide in Scotland.

Lothians Independent MSP Margo MacDonald will bring her End of Life Choices Bill before Holyrood on Thursday after Presiding Officer Alex Ferguson gave a late ruling that the proposals were legally competent and fit for scrutiny.

Ms MacDonald suffers from Parkinson's Disease and has said she would like the right to end her own life should her condition deteriorate.

Speaking before the formal launch, she said: "It is undoubtedly an issue which is currently, and has increasingly, been of interest to the general public.

"There are now too many opinion polls indicating support for the notion of patient autonomy in the matter of assisted death."

Her proposals would allow people with progressive degenerative conditions, and those with a terminal illness which has made life intolerable, to ask a doctor to help them end their life.

Proposed safeguards would mean a patient would have to approach a suitably registered doctor, who would then consult a specialist to decide whether the patient was capable of making an educated decision.

Doctors who objected to assisted suicide on moral or religious grounds would have no legal obligation to help a patient to end their life.

First Minister Alex Salmond has admitted he is "not convinced" by Ms MacDonald's argument. However, he has said he will allow all Government minister a free vote of conscience on the issue.

All of the other parties in Holyrood have given similar assurances, saying all MSPs will be able to vote freely rather than in line with party guidance.

The Bill has attracted the support of MSPs across the political spectrum since it was first proposed 10 months ago. A public poll in November also showed that more than two-thirds of people would back a change in the law.

However, some campaigners have argued against the move, with the Care Not Killing alliance arguing a change in the law could put some terminally-ill people under pressure to take their own life prematurely.

Dr Gordon Macdonald of Care Not Killing urged Holyrood to proceed with "extreme care and caution" when considering the Bill, branding Ms MacDonald's proposals  "highly dangerous".

Dr Macdonald said: "Euthanasia laws may meet the wishes of a small minority of strong-minded and highly-determined individuals, but they risk placing many more, less resolute people at risk either of malicious exploitation by others or of ending their lives against their own instincts in order to spare others a financial or emotional burden."

The Scottish Council on Human Bioethics said the Bill would mean human lives "no longer have meaning, value or worth".

There are currently no legal guidelines on assisted suicide in Scotland, meaning people who help a loved one to end their life could be prosecuted under culpable homicide laws.