As head of Shelter, the charity for the homeless, Dame Sheila McKechnie became a thorn in the side of Conservative governments, and her time in charge of the Consumers' Association saw that organisation develop into a considerable force for change.
She was born in Falkirk in 1948 to a working class, left-leaning family. Her feminism came naturally, she once said, having been surrounded by strong women and weak men.
Though she was an atheist, she often attributed her zeal for campaigning for social justice to a "streak of Calvinism".
At Edinburgh University, where she read politics and history, she was known as "Legs McKechnie", for her six-foot height and her penchant for wearing mini-skirts.
After gaining an MA in industrial relations at Warwick, she toyed with the idea of a career with the Civil Service before choosing trade unionism.
She transformed the homeless charity, Shelter
She began with the small Wallpaper Workers Union before moving to the white-collar ASTMS union. Here she spent nine years as health and safety officer, campaigning for higher standards of safety in laboratories, and for sexual equality in the workplace.
Her big break came in 1985, when she was offered the post of director of Shelter, which had fallen on hard times.
Knowing little about housing, she had gained a reputation as a formidable organiser.
Though she upset many with her abrasive personality and short-temper, she established the charity on a more professional basis, ridding it of its "moaning lefties" image.
She was highly critical of the Thatcher government's "right-to-buy" policy, for example, yet the charity gained the government's respect.
By the time she left to become director of the Consumers' Association after 10 years, Shelter's turnover had increased from £1m to £10m.
McKechnie's combative nature, and by now, highly proficient administrative and media skills, were then turned towards mobilising the "sleeping giant of consumer power".
She campaigned against the high UK cost of cars
Famous for its Which? Guide to products and services, Sheila McKechnie introduced an online version, a credit card and a telephone service which was soon taking 4,000 calls a day.
It also extended its range to take on the bad practices of corporate business.
In one memorable action during a long campaign against the high price of cars in Britain, she appeared at the London HQ of the Society of Motor Manufacturers and Traders in a Ford Focus painted with a Union Jack with the message "The Great British Rip-Off" plastered all over it.
Latterly, the CA's wrath has been directed towards financial services. In 2000, Which? Magazine named and shamed the 10 mortgage lenders which had received the most complaints from customers.
It has been involved, centrally, in exposing the scandal of the mis-selling of endowment and pension policies.
In 2001, she suggested life insurance actuaries were no more trustworthy than Dr Harold Shipman.
Sheila McKechnie's social standing became such that in 1998, the Chancellor, Gordon Brown, appointed her as one of six new non-executive directors to the Bank of England's court.
And in 2001, she was made a Dame in the Birthday Honours List.
Sheila McKechnie was a woman with great drive and outgoing personality. She once said: "To be paid to take on all these issues of unfairness and injustice is something incredibly worthwhile socially and very fulfilling personally."