Margo MacDonald's politics were those of independence, but that quality ran through her more deeply.

A woman of forthright opinions who loved to persuade others to her point of view, it was characteristic that, on being diagnosed with a terminally degenerative illness, her response was a renewed dedication to bring about social change.

Although her victory for the Scottish National Party at Govan in 1973's by-election was significant and has remained a landmark moment in the rise of the SNP, she was always an awkward figurehead.

Initially a PE teacher, she could claim to have had a "real job" despite forging a career in politics. In any case, she did not became a career politician, either of the sort who climbs a party hierarchy and clings to office by any means possible, or of the type who slavishly adjusts their opinions to adhere to party discipline.

Instead she quit the SNP three years after rising to the position of deputy leader. She was officially expelled from the SNP in 2003 after being one of its first MSPs, in a "rainbow" parliament that featured representatives of the SSP and Green Party, and Dennis Canavan sitting as an independent.

In retrospect, her expulsion looks like a misreading of the public mood. Having rejoined the SNP, she was effectively sidelined by being given a position on the party list that would deny her a real chance of a seat.

Over three subsequent elections she stood as an independent, eventually becoming the last one standing, as that initial shattering of the party model failed to be sustained.

Public admiration for a principled politician outweighed the need for a party machine. That strong personal support is surely why, outside the party again, she was able to win her seat back in three successive elections.

Freed to follow her own ideas and principles, she was terrier-like in pursuit of answers about the inflated spending on the Scottish Parliament building, took a stand in favour of tolerance zones to increase the safety of sex workers and then became dedicated to the cause of legalising assisted suicide for the terminally ill.

Despite dying before seeing a result from this campaign, she made use of her broadcasting experience to raise the profile of the issue and should the law eventually be changed, her role will have been significant.

It is stating the obvious to observe that she will be missed - by her constituents, by parliamentary colleagues, by her similarly free-thinking husband Jim Sillars, and by many more who encountered her inside and outside politics.

But in the midst of an independence debate that is still failing to rouse a sizeable proportion of the population , it is instructive to consider the way she made and kept a connection with her constituents - through honest, strong-minded views, often held in defiance of spin doctors and party whips.

Because they knew she believed in what she said, voters identified with her and felt she represented them in a way only a minority of politicians ever manage, and many of her political peers not only would but should envy.