AS you might imagine, I have a computer and, on it, I keep files of these lectures or homilies. If the Icon is a person, the file title will have the full name. This one just has “Margo”.

A confession: during many years as a sketch-writer at Holyrood, I never hobnobbed with MSPs, as I felt it might blunt my pen. Never, except twice: I’d a pint with Lib Dem Tavish Scott, whom I knew already; and I had lunch with Margo.

Actually, three times: I’d a pint with Alex Salmond. He was upset with my description of his flyaway eyebrows (“like two Spitfires peeling off in battle”). Wish I’d never started this. My purity is oot the windae. But you get my drift. Such hobnobbing was exceptionally rare.

And so was Margo. A one-off, as they say. Margo Symington MacDonald (née Aitken), to use her full handle: like the best people, she supported Hibs, but she also had an interest in politics, and that’s doubtless what you’ll know her for.

Born in Hamilton, South Lanarkshire, on 19 April 1943, she was educated at Hamilton Academy, then trained as a gym teacher at Dunfermline College of Physical Education. In 1973, aged 30, the “blonde bombshell”, as you wouldn’t be allowed to say today, won the then Labour stronghold of Glasgow Govan for the SNP amid “scenes of near-hysteria”.

In the Commons, Margo joined the only other SNP MP, Donald Stewart (Western Isles), though she was less happy at other alleged company, claiming KGB and CIA agents took her for lunch while posing as journalists – not your correspondent, I should stress.

She also believed the SNP was infiltrated in the 1970s by MI5 and, during the 2014 Scottish independence referendum, suggested the security services "have people in the SNP”. They were the ones in kilts.

In her Commons maiden speech, Margo, later a director of homeless charity Shelter, recalled that her Labour predecessor, John Rankin, had spoken about housing problems in 1945. Nearly 30 years later, the same “shameful facts” were still self-evident in Govan.

Margo herself was turfed out of the House when Govan returned to Labour at the February 1974 election. That year, she became SNP deputy leader and, noting the party’s failure to win seats from Labour in industrial areas, tried shifting it leftwards. However, even with her socialist credentials, she failed to move the Scottish proletariat, losing in the 1978 Hamilton by-election and the 1979 general election, when standing for Glasgow Shettleston.

Worse still, having become a prominent supporter of the socialist 79 Group, she was heavily defeated in her attempt to be re-elected as deputy leader. In 1982, after the group was banned, she resigned from the party in protest but remained in the public eye as a characterful radio and television presenter. Later, she was reduced to writing newspaper columns.

By the mid-1990s, she was back in the SNP and, in 1999, was invited to stand for Edinburgh South in the first Holyrood elections – despite, according to her husband Jim Sillars (another fiercely independent political dynamo), a determined campaign by leader Alex Salmond to stop her.

She won the selection vote 25-0 and, while she didn’t win the constituency, she became a list MP for Lothian. Margo remained at odds with the party leadership which, in the 2003 election, placed her fifth on the Lothian list, effectively ending her chance of re-election. Or so they thought.

Standing as an independent, Margo won 27,000 second votes on the regional list and secured re-election, as she did again in 2007 and 2011. Around 2002, her Parkinson’s disease, diagnosed years earlier and kept secret from her grandchildren, became public knowledge. She said it had been leaked to the press by "forces of darkness”. But the SNP denied it came from them. In his memoirs, A Difference of Opinion, Jim Sillars said that, in her later years, Margo was “very forgiving of those who had leaked the story”.

At Holyrood, meanwhile, there were campaigns to be fought, and not just for Scottish independence. She championed sex workers’ rights, introducing a bill to legalise “tolerance zones”. She was a critic of the Holyrood building project, and her search for the “smoking trowel” led to the Fraser Inquiry, which had the power to name and shame anyone declining to give evidence. Margo: “The problem is, some of the folk he [Lord Fraser] might name have no shame.”

Less high-profile causes included bringing HMS Edinburgh – a decommissioned warship – back to the capital as a tourist attraction, and banning vuvuzelas at Scottish football grounds. Latterly, though, her best-known campaign was for assisted dying as a choice for the terminally ill.

In March 2008, she told Parliament: "I don't want to burden any doctor. I don't want to burden any friend or family member.” Though her right-to-die bill was rejected in a free vote, Margo pursued the cause to the end, which came peacefully at home surrounded by her family, in Edinburgh on 4 April 2014. She was 70.

Tributes came from across the political spectrum. Scottish Labour leader Johann Lamont said: “She came as close to a political treasure in Scotland as I think it is possible to be.” Scottish Conservative leader Ruth Davidson described her as “humorous and warm – passionate about … the better Scotland she wanted to help build”.

The Lib Dems’ Willie Rennie added: “The affection for her transcends party politics and political parties.” And First Minister Alex Salmond praised her as “one of the great rallying figures of Scottish nationalism”.

In his memoir, Jim Sillars recalls: “In her last days, the one thing that pleased her most was a private visit from Alex Salmond. Her relationship with him, like mine, had deteriorated but her getting back onto the old footing one last time meant a very great deal to both of us.”

Margo was her own woman. She wanted Scotland to be its own country. But she did not want antagonism. The “Margo MacDonald way”, as outlined by Mr Sillars, was “to realise that your are dealing with opponents, not enemies; not with ogres, but with fellow human beings, with whom you can disagree but do so without malice”.