Few political leaders have the honour of getting an ideology named after them. But Thatcherism has defined Britain, for better or worse, for the decades during and since her premiership.
Margaret Thatcher was the woman who, virtually single-handed and in the space of one tumultuous decade, transformed a nation.
Her supporters believe she put the drive back into the British people. Her detractors, just as vociferous, saw her as the personification of the uncaring new political philosophy.
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.
Her fall from grace came in 1990, a year in which she faced a series of damaging resignations from the Cabinet, her own political judgments were publicly denounced by her own colleagues, catastrophic by-election humiliations, internal party strife, and a sense in the country that people had had enough of her after 11 years in power.
But history will almost certainly proclaim her as one of the greatest British peacetime leaders.
And as she transformed the nation - attempting to release the grip of the state on massive industries and public services alike - she strode the earth as one of the most influential, talked-about, listened-to and dominant statesmen of the Western world.
When Argentina invaded the Falklands, she despatched a task force to the South Atlantic which drove the enemy off the islands in an incomparable military operation 8,000 miles from home.
She successfully defied Arthur Scargill's nationwide and year-long miners' strike, which threatened to cripple Britain's entire economic base.
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.
Instead she stripped the unions of many of their powers with the aim of transferring them to managements and individual consumers.
Within weeks of her arrival in Downing Street, foreign correspondents from all points of the globe - absent for so long from the House of Commons - flocked back to the press gallery.
It was a sure sign that the world was sitting up and listening once again to what Britain had to say.
Whether you liked Mrs Thatcher or loathed her - and her Tory predecessor Edward Heath hated her beyond belief - whether you agreed with her or found her policies utterly repugnant, you could not deny her energy and drive.
Even many political foes secretly admired this single-minded woman, who never contemplated defeat and for whom all issues were black and white, not hedged about with grey.
Even - indeed particularly - her most bitter political enemies were forced to praise her crusading clarity of purpose and her determination, in their eyes, to serve "her people".
Veteran left winger Tony Benn frequently held her up as an example of how a great political party should be led, comparing her with what he regarded as Neil Kinnock's fudged leadership of the Labour Party.
Margaret Thatcher towered above all other political figures in Britain and her dominance of the Cabinet was supreme and rarely challenged. She was the equal of statesmen across the world. She elevated Downing Street to something like the status of the White House and the Kremlin, symbols of the then two great superpowers. Nobody talked down to her.
Yet the Iron Lady - a title bestowed upon her by her enemies in Moscow, which, incidentally she relished - was not all stern, steely and strident. She was delightful with children and she could not disguise her glee - "We are a grandmother" - when her grandson Michael was born in Dallas in February, 1989.
She regularly and touchingly admitted that she could not do her job properly without the unfailing and unstinting support of her "marvellous" husband, Denis. He was, she said, the "golden thread" running through her life.
His death, in June 2003, some weeks after major heart surgery, was a profound blow to her.
Sir Denis, as he became after she left Downing Street, was constantly at her side, an impeccable consort, protecting her and guiding her in all weathers and in all parts of the world.
He was a wonderful source of encouragement and comfort to her when, as sometimes happened, she returned home in tears after a particularly gruelling day. He made no attempt to disguise his contempt for those who opposed his wife, but he never got involved publicly in policy or political discussions.
His death came at a time when Margaret Thatcher's own health - she was ten years younger than him - was the subject of speculation. She had suffered a series of strokes and her doctors had forbidden her to make any more speeches - instructions which she was occasionally known to breach.
Sir Denis's death was a massive blow to Lady Thatcher. But there was more grim trouble ahead.
Her son, Sir Mark - he inherited the baronetcy from his father - was charged in South Africa in connection with a plot to overthrow the Government of oil-rich Equatorial Guinea. The charge carried a maximum penalty of 15 years, and possible death if Sir Mark was extradited to Equatorial Guinea.
The news broke when Lady Thatcher was on holiday in the United States. She doted on her son and the charge plainly devastated her.
However, after weeks under house arrest in Capetown, where he lived, Mark in January 2005, pleaded guilty to unwittingly helping to finance a foiled coup plot in oil-rich Equatorial Guinea. He accepted a three million rand fine and a suspended jail sentence.
Thatcher always conceded that personal attacks on her, and particularly on members of her family, wounded her deeply.
And yet the woman who took on Argentina and who had the people of Moscow reaching out and yearning to touch her, could not bear the sight of creepy-crawlies or snakes.
Mrs Thatcher was obsessively British, batting for Britain wherever she went, wearing exquisite home-produced clothes, upbraiding those who did not, and turning up her nose at the French Perrier Water. "What's wrong with British water?" she demanded.
Her dramatic downfall came about during the second of two challenges to her leadership. She realised that if she stayed on to take her challenger Michael Heseltine - a man she disliked intensely, personally and politically - into a second ballot, he would almost certainly supplant her. That was a prospect she could not bear to see happen.
And so, after consulting her Cabinet colleagues, one by one, she decided she must go, and tearfully gave the Cabinet the news the following morning.
By doing so, she paved the way for one of her favourite "sons" John Major to follow her into 10, Downing Street.
But her support for him was luke-warm. She was to say later that she backed him because he was "the best of a poor bunch".
She marked her decision to quit with the historic expression: "It's a funny old world" - pointing out that she had been summarily removed from power even though she had won every election she had fought.
Some of her friends believed that her decision to go to Paris, rather than remain in Westminster, during that first fateful ballot, demonstrated an arrogance and a misjudgment which may well have cost her those crucial handful of votes which would have kept her in Downing Street. If she had received just four more votes, there would have been no need for a second ballot.
But there was no let-up in her energetic activities once she arrived in the House of Lords. She remained a ferocious critic of the European Union, and led a crusade in the Upper House against the Maastricht Treaty.
She was accused, as well, of attacking her successor, John Major, in the same way that her predecessor, Sir Edward Heath, had constantly criticised her when she was in power. But her strictures on John Major did not carry the bitterness and resentment of Heath's criticisms of her.
Years later, she was to be praised by two Labour Prime Ministers, Tony Blair and Gordon Brown, both of whom invited her into Downing Street soon after they came to power. These were events which enraged some factions in the Labour Party.
Baroness Thatcher maintained a gruelling programme of lecture tours worldwide, showing little, if any, sign of slowing down her scorching pace. But there were moments when her stamina and health came into question.
Once, in 1994, she collapsed in the middle of a speech in Santiago, Chile. but she shrugged off warnings from her friends that she should start to take things more easily.
And later that year, her friends were shocked at her gaunt and haggard aspect, three days before her 69th birthday, when she made a token appearance on the platform of the Tory Party conference in Bournemouth.
Her response to that renewed expression of alarm among her supporters was to dash off on another exhausting global speaking tour.
But there was little doubt that her health was affected by the combination of a massive four-hour dental operation, an enforced diet, and worry about reports of her son Mark's alleged profiteering from Middle East arms deals she had negotiated as Prime Minister, as well as the apparently impending break-up of his marriage. But those reports came to nothing.
Neither age nor anything else was going to stop this woman from expressing herself vigorously and passionately whenever she felt the need. In 1997, she derided the British Airways decision to introduce "modern art" on the tailfins of their fleet instead of the symbol of the Union Flag.
She famously covered one of these offending tailfins on the model of an aircraft with a handkerchief while touring the stalls at the Tory Party conference.
And in October, 1998 she called for the immediate release of ex-President Pinochet of Chile, who was being held to face an extradition request by Spain for alleged murder.
Baroness Thatcher said he saved many British lives during the Falklands conflict, that Chile was "a good friend to this country" and that Pinochet must be allowed to return to his own country forthwith.
She caused a stir by visiting the former Chilean leader while he was effectively under house arrest near London, and having lunch with him. But her appeals to the then Home Secretary Jack Straw were ignored.
Before that, in a last-minute move, she backed the Tory leadership campaign of William Hague, support which may have helped him to defeat his rivals by an unexpectedly large margin.
THATCHER'S EARLY LIFE
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."
Not only that, but she acted on it. For it was her colossal industry, her almost innocent belief that all her objectives not only could but would be achieved which launched her into a political career unsurpassed by any woman before her - and precious few men as well.
Her associates at school and university - she had few close friends - recall her as industrious, serious-minded, and soberly-dressed, but also possessing what one of them has since described as "an irritating sense of her own superiority".
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.
Her principal at Oxford fell short of wild enthusiasm for her abilities, describing her as "a perfectly good second-class scientist".
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.
Mrs Thatcher launched into her battle to get into Parliament by unsuccessfully fighting Dartford - where she met Denis - in 1950 and again in 1951. Their twins, Mark and Carol, were born by Caesarean operation.
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.
Thatcher epitomised then, as she did throughout her career, the self-made woman.
Once she said contemptuously: "I owe nothing to Women's Lib" when she was criticised by feminists.
In the final years of the Harold Macmillan-Alec Douglas-Home administrations, Mrs Thatcher was parliamentary secretary, Ministry of Pensions and National Insurance.
When the Heath administration took office in 1970, Mrs Thatcher became Education Secretary, a key job in the new cabinet.
Here, she worked uneasily. Her natural desire to give people independence and self-reliance was constrained - and had to be - by the collective approach of a Government much more timid than her own administrations were to be.
Even so, she quickly became a hate figure on the Labour benches, branded as "Thatcher the Milk Snatcher" because of her decision to stop free milk for primary schoolchildren.
The two disasters that befell the Conservatives - general election defeats in February and October 1974 under the uninspiring leadership of Heath - gave Mrs Thatcher the opportunity she so desperately sought.
There was now widespread dissatisfaction with Mr Heath.
The word quickly went around that Mrs Thatcher would be bold enough to challenge him.
It is arguable that if she had not been so intrepid, none of her timid colleagues would have dared to challenge him.
But by now she was the darling of Tory rank-and-file MPs sickened by what they regarded as the wishy-washy Heath brand of Conservatism. They were struck with admiration at her valour.
She made short work of defeating the lugubrious, lovable Willie Whitelaw - he wept when he was beaten - who epitomised languor and lethargy. And so, in 1975 she became the first woman at the helm of the Conservative Party, hell-bent on seeing the Tories back in power.
Mrs Thatcher drove in triumph that night in 1975 from the House of Commons to Conservative Central Office where she straightaway set in train an unstoppable campaign whose momentum, four years later, was to pitch her into power.
First Harold Wilson and then his successor James Callaghan quickly found they had a sweetly snarling tigress to deal with at the Despatch Box, compared with the lumbering bear that was Edward Heath.
She injected new heart, spirit and fire into the Conservative Party. Meanwhile Labour staggered from one crisis to another, winding up with the so-called 1978-79 winter of discontent, during which strikers even refused to bury the dead and with the Government seemingly impotent to act.
To crown it all Callaghan returned to the grime and snow of strike-ravaged Britain from an indulgent summit in the tropical sunshine of Guadeloupe and was reported as saying: "Crisis? What crisis?"
The words were, in fact, a headline in the following day's Sun newspaper. But from that moment on he, too, was a doomed man.
Within months, Mrs Thatcher, aged 53, was stepping into Downing Street, softly quoting from memory the exquisite prayer of St Francis of Assisi: "Where there is discord, may we bring harmony. Where there is error, may we bring truth. Where there is doubt, may we bring faith. Where there is despair, may we bring hope."
She had belied her prediction seven years earlier, when questioned about the likelihood of there being a woman Prime Minister. She had said then: "I don't think it will come for many, many years. I don't think it will come in my lifetime."
"Unnamed sources" always said that she treated her colleagues - and civil servants - abominably. That was never true. She relished a fight, she usually won, but was courteous in all her personal encounters.
But she respected - and listened to - those of her colleagues who stood up to her. After she left power, volume after volume of political memoirs, from embittered and angry former Cabinet Ministers in her administrations, described fearsome storms within the Cabinet and without.
Significantly she never had a woman in her Cabinet who wielded any influence of any consequence. Baroness Young was the only woman to reach her Cabinet, and then only briefly, as Leader of the House of Lords: a post which carried virtually no authority within the Government.
Thatcher could not handle women, but shamelessly exploited her feminine wiles as well as her innate dominance to succumb or win over her male Cabinet colleagues.
When President Reagan arrived on the scene there was an instant rapport, a close and abiding friendship which endured long after he left office and continued until his death.
She remained friendly with his widow, Nancy and the two met from time to time.
The warmth between Reagan and Thatcher was remarkable and during that period the "special relationship" between Britain and the United States was very special indeed.