In the view of her admirers, she thrust a strike-infested Britain back among the front-runners of the industrial nations of the world.
Her detractors, many of them just as vociferous, saw her as the personification of an uncaring new political philosophy known by both sides as Thatcherism.
Across the Calendar region she will probably be best remembered as the Prime Minister who successfully defied Arthur Scargill's nationwide and year-long miners' strike, which threatened to cripple Britain's entire economic base.
Tireless, fearless, unshakeable and always in command, she was Britain's first woman Prime Minister - and the first leader to win three General Elections in a row.
Mrs Thatcher, who became Baroness Thatcher, resigned as Prime Minister in November 1990 after a year in which her fortunes plummeted.
Margaret Hilda Roberts was born in 1925 in the Lincolnshire town of Grantham. She quickly had the virtues of thrift, hard work, morality and patriotism drilled into her by her beloved father Alderman Alfred Roberts, who ran two grocers' shops and a post-office, and became mayor of the town in 1943.
Alderman Roberts was a devout Methodist, a lay preacher and a proudly self-made man. Margaret never forgot - and throughout her career never tired of quoting - his words to her: "You'll never get anywhere if you don't work, girl."
Inevitably she became head girl at Kesteven and Grantham Girls' High School. She went on a bursary to Somerville College, Oxford, where she read chemistry.
However, she went on to become only the third woman president of the University's Conservative Association. She continued to work as a chemist until 1954 when she switched to become a barrister specialising in tax cases.
She finally entered the Commons in 1959 as Member for Finchley, a seat she represented throughout her career as an MP. The smartly-dressed, brisk and businesslike blonde did not remain unnoticed for long. She swiftly adapted to the strange ways of Westminster. Her friendly manner and warmth belied and disguised the white heat of her ambition.
Her triumphant achievement of power in May 1979 signalled the end of the era when trade union leaders trooped in and out of 10, Downing Street, haggling and bargaining with her Labour predecessors.