The 1980s set the mould for Britain today - the defeat of grit, soot, smoke and clank; the triumph of credit and rampant consumerism. But the instigator of this revolution didn't plan it that way, says Andrew Marr, whose TV history of post-war UK continues on Tuesday.
In politics, if your tactics work and if you are lucky, then you will be remembered for your principles.
Margaret Thatcher's tactics did work; she was shrewd, manipulative and bold, verging on reckless.
She was also extremely lucky. Had Labour not been busy disembowelling itself and had a corrupt, desperate dictatorship in South America not taken a nationalistic gamble with some island sheep-farmers, her government would have been destroyed after a single term.
Had the majority in her cabinet who disagreed with her about the economy been prepared to say boo to a goose, she might have been forced out even before that.
In either case her principles, "Thatcherism", would have ended up a half-forgotten doctrine, mumbled about by historians instead of being the single most potent medicine ever spooned down the gagging post-war British.
Looking back more than a quarter of a century later, the epic events of the early 80s have a clear, inevitable pattern.
Powerful ideas challenge the consensus and after a nail-biting struggle, defeat the consensus.
The early reverses of the Thatcherites, the "New Right" promising "a New Enlightenment", are turned into massive, nation-changing victories.
Yet if you stand back and ask what sort of Britain Mrs Thatcher, the grocer's daughter, the devout Lincolnshire Christian, hoped to create, the story is odder.
She did not believe in privatising industries or defeating inflation for merely economic reasons.
She wanted to remoralise society, creating a nation whose Victorian values were expressed through secure marriages, self-reliance and savings, restraint, good neighbourliness, hard work.
The bitter miners' dispute ended in defeat
Though much attacked by church leaders she talked of God and morality a lot: "I am in politics because of the conflict between good and evil."
Yet Thatcherism was the bell-ringing herald of an age of unparalleled consumption, credit, show-off wealth, quick bucks and sexual libertinism. When you free people, you can never be sure what you are freeing them for.
Two Britains emerged in the 1980s. The rich got richer but the bottom 10% saw their incomes fall by about 17%. A lot of people fell through the cracks. Once Britain had prided itself on not seeing people sleeping on the streets or begging. Not anymore.
Thatcher set her sights on one of the few socialist enemies left standing. When the bitter miners' dispute ended in their defeat in 1985, Thatcher pressed ahead with the pit closure programme until deep mining in Britain was over.
An industry whose origins went back to the Middle Ages, upon which Britain's industrial greatness had been raised up, now laid down and died.
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The world of heavy industry, heavy men and heavy unions was no longer, it seemed, wanted.
This was a defeat for the industrialised Britain of brick terraces, grit, soot and smoke and clank, making way now for a new economy - un-unionised, privatised, white-collar, the service economy, the blander, virtual economy.
The City of London became the cockpit of the new economy. In the age of Macmillan and Wilson the Square Mile had become part of heritage Britain, its declining firms like the cashless Palladian houses of Oxfordshire, in which grumpy men with famous names stamped their feet against the cold and mentally apologised to grandpapa.
It was this world which was swept away on 23 October 1979 when Geoffrey Howe, to general shock, abolished exchange controls, which prevented British people from taking capital abroad and stopped institutions from investing capital abroad without special Treasury permission.
The raucous 'barrow boys' pumped up on booze, cocaine and fear of failure who became such an emblem of 80s...
Despite what she later said, Thatcher was wobbly and uncertain about the gamble. Howe himself likened it to walking off a cliff to see what happened.
In 1982, another slice of American business life came to London in the multi-coloured jackets and raucous bear-pit atmosphere of the new international financial futures market, or Liffe.
Here the high-risk bets were made on the future value of commodities and currencies, in one of the older buildings of the City, the Royal Exchange.
Inside its elegant shell roared an atmosphere borrowed straight from Chicago, likened by startled observers at the time to an ill-bred casino.
Liffe would turn out to be very profitable for the traders, the raucous "barrow boys" pumped up on booze, cocaine and fear of failure who became such an emblem of 80s life, many retiring exhausted and vastly rich by their early 30s.
For millions of ordinary Britons who had only the haziest idea about the world of finance, the revolution in lending for houses was as big a shock.
Until the early 80s, most people's experience of getting a mortgage involved a barrage of suspicious questions from a building society manager, followed by a long wait (for the loans were rationed and people had to queue to get one) and eventually followed by a mortgage whose cost was fixed by the Building Societies Association.
The Liffe floor transformed the City
Generally speaking, the size of the low-cost loan, funded by deposits from building society members, would be limited to two-and-a-half times the would-be homeowner's annual salary.
Would-be borrowers limped along with an ingratiating cringe to the local building society and patiently endured many obstacles before they were allowed a mortgage.
Now the building societies and banks started to ingratiate themselves with the public, thrusting credit at them. It became a good thing, a virtuous thing, to be a big-time borrower.
The old rules about the maximum proportion of income began to dissolve - four times income began to be acceptable in some cases. House prices began to rise accordingly.
The sight of people sleeping rough became more common
The old system of checking people's real financial status went out of the window.
During 1986-88 a borrowing frenzy gripped the country, egged on by swaggering speeches about Britain's economic miracle from the chancellor and prime minister.
All this would end in tears with the bust that followed and which would be used for many years afterwards by Labour's Gordon Brown as evidence of the Tory "boom-and-bust" policies.
But it was the consequence of a decisive break in the financial regulations governing City and everyday life, which changed Britain, probably forever.
It felt heady and exhilarating to millions. It was like getting properly drunk for the first time.
Andrew Marr's History of Modern Britain continues on BBC Two on Tuesday, 12 June, at 2100 BST.
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