The charismatic former deputy leader of the SNP, who was regarded with respect and affection across the political spectrum, had been battling Parkinson’s disease for 20 years.
Her husband, Jim Sillars, a former SNP MP, said: “She leaves a void in our lives which will be impossible to fill and her death robs the Scottish nation of one of its greatest talents.
“She was without question the most able politician of her generation. Today, the brightest light in the Scottish political firmament has gone out.”
Ms MacDonald’s death, at 70, sparked a flood of tributes from former colleagues, public figures and opponents, who spoke of their admiration for one of Scotland’s most beloved and colourful politicians.
She was diagnosed with the degenerative illness Parkinson’s in 2002 but even as her condition deteriorated, it failed to distract her from her work as an independent MSP for Lothian.
Only last week, First Minister Alex Salmond visited her at home to discuss strategy for the 18 September independence referendum – an event that she fought for all her life, but did not live long enough to witness.
Ms MacDonald burst on to the political stage in 1973 when she won Govan from Labour for the SNP – a triumph her husband, who also served as SNP deputy leader, would repeat in 1988.
Her career as a Westminster MP only lasted 112 days, because she lost her seat at the 1974 general election. But by then the sensational nature of her Govan victory and the force of her personality as well as her striking looks had earned her the nickname “the Blonde Bombshell”.
The establishment of the Scottish Parliament in 1999 saw her return as a front-line politician representing the SNP. But after falling out with the party leadership, she successfully stood at Holyrood as an independent MSP on the Lothians list in three Scottish elections.
As an independent MSP, she fought for Scottish independence, but was unafraid to criticise the SNP. Despite her health problems, she continued to work tirelessly for the causes close to her heart, including her deeply personal bid to legalise assisted suicide in Scotland.
Mr Sillars said his wife’s legacy would “speak for itself”, adding: “She supported and inspired generations of idealists and campaigners who, like her, wanted Scotland to take its place in the world. Her talent acted like a magnet and she gave her time so freely to so many for so long.”
While he said many would mourn her, he added: “The pain of loss will be borne most of all by those at the heart of her life – her children and her grandchildren. We will do all we can to honour her memory.”
Mr Salmond, who is in the US, paid tribute to the politician with whom he had many robust exchanges. The First Minister hailed Ms MacDonald as “one of the great rallying figures of Scottish nationalism”. He added: “From her Govan by-election victory in 1973 she had a profound role in Scotland’s home-rule journey. Very few politicians are recognised and known to the public by their first name – Margo was. Even fewer have the profile and talent to be elected comprehensively as an independent candidate – Margo had.
“I saw her only last week to talk tactics on the independence referendum. Despite great physical infirmity, she dispensed wise advice and her enthusiasm and commitment to the independence cause was bright and undimmed.”
From the other side of the political divide, the Better Together leader Alistair Darling said: “Margo was one of the warmest and most compassionate women I ever met. She was also one of the most determined and formidable Scottish politicians of her generation. I shall miss her very much. My thoughts are with Jim and the family.”
Under normal circumstances, the death of a list MSP would see another candidate from the late politician’s party enter parliament. As Ms MacDonald was a independent, her seat will remain vacant until the next Scottish election.
Her member’s bill on assisted suicide will continue to be considered by Holyrood.
Before entering politics, Ms MacDonald trained and worked as a PE teacher. She became deputy leader of the SNP in 1974, the year that she lost her Govan seat.
Firmly on the left of the party, she stayed in the post until 1979. In 1982, she left the SNP for the first time when the socialist 79 Group, of which she was a member, was proscribed by the party.
Away from politics, she forged a career as a broadcaster and journalist until devolution saw her return as an SNP MSP.
Never one to dodge controversy, she campaigned for tolerance zones for prostitution and was one of the most vocal critics of the spiralling cost of the Scottish Parliament building. Last night, flags outside the Holyrood parliament flew at half mast.
A passionate supporter of Hibernian, she was heavily involved in the “Hands off Hibs” group, which campaigned for the club in the 1990s. Even when seriously ill, she was a highly influential figure at Holyrood, zipping around on her motability scooter.
At the end of a day’s work, she was often an entertaining presence in the Holyrood bar, which journalists nicknamed “Margo’s” in her honour.
The parliament’s Presiding Officer Tricia Marwick said: “To be known and recognised by a first name is reserved to very few. But everyone knew Margo. She had a rare skill in being able to translate political-speak into language we could all understand. Margo cared about people and, in return, they cared about her.”
Scottish Conservative leader Ruth Davidson said: “Margo MacDonald was a huge figure in Scottish politics and a one-off.
“She sat as an independent, and independent she was – independent of thought, independent of mind and independent of spirit.”
Ms Davidson added: “From prostitution to assisted suicide, she was willing to champion difficult, challenging and morally complex issues.”
Johann Lamont, the Scottish Labour leader, said: “Margo’s passing sees a bright light, and one of the biggest personalities and characters of Scottish modern political life, go out.
“Her sense of humour, passion, integrity and unflinching desire to speak truth to power meant she came as close to a political treasure in Scotland as I think it is possible to be.”
The Church of Scotland Moderator, the Rt Rev Lorna Hood, said: “Although we in the church hold different views, we are grateful to her for bringing end-of-life issues into the public arena, particularly in our care for those nearing death.
“Margo was a guest at a dinner I hosted a few months ago on end-of-life issues. She was spirited and entertaining and spoke with great conviction about her beliefs. By the end of the evening, a palliative care consultant opposed to Margo’s position said she’d realised their views weren’t so far apart after all.
“Scotland is poorer for Margo’s passing, and our love, care and heartfelt prayers go to Jim and the family.”
Details of the funeral will be announced next week.
Margo MacDonald profile
Margo MacDonald first came to national prominence in Scotland when she famously won the Glasgow Govan by-election for the SNP in 1973, triumphing in what had been regarded a Labour stronghold.
She had previously been a PE teacher, before defeating Labour’s Harry Selby by fewer than 1,000 votes.
She failed to hold on to the seat in the 1974 general election, but went onto become SNP deputy leader.
A political left-winger, she was prominent in the socialist 79 Group, which also included a young Alex Salmond. She eventually left the party in 1982 after a series of spats.
Ms MacDonald went on to carve out a career as a presenter of radio and television programmes. It was during this period that she married the former Labour MP Jim Sillars.
She later returned to the SNP fold with the advent of devolution and was elected as an MSP for the Lothians in the first Scottish Parliament in 1999. But she fell out with the SNP leadership again over a newspaper article about French National Front leader Jean Marie Le Pen and went on to stand as an independent on the regional list, after effectively being de-selected. She not only won, but was successfully re-elected as an independent MSP in 2007 and 2011 - the only one at Holyrood.
She turned her attention to causes she felt passionate about during this period. This included assisted dying which she wanted to see legalised in Scotland. She herself had been diagnosed with Parkinson’s in 2002 and revealed she wanted the option of being helped to die if her condition deteriorated. Mrs MacDonald also backed the introduction of prostitution tolerance zones and was also a tenacious critic of the spiralling costs of the £400million Holyrood building.