She inspired love and loathing in equal measure, but there is one thing on which both the lovers and the loathers would agree: Margaret Thatcher did change Britain, something that prime ministers seldom succeed in doing.
For those that loved Maggie, there can be no doubt she was the greatest peacetime leader of the 20th century. When she came into office in 1979, she found a country demoralised by failure, weighed down with burdens it could no longer bear, unable to offer its people any assurance of reward for honest effort.
When she went out of office in 1990, the country had undergone a political renewal not only on the Right but also on the Left, had seen the animal spirits of capitalism reawakened and had reasserted itself as a power to reckon with everywhere from Moscow to Washington, from Brussels to Buenos Aires.
Her premiership had been epoch-making. The 20th century was still late on a period of decline for Britain, from imperial greatness at the beginning through two world wars that cost us dear, where indeed victory turned out only a little less economically devastating than defeat would have been. The period after 1945, for all its achievements in reconstruction, did not lift a pervasive gloomy atmosphere of dwindling and decadence.
One of Maggie’s assets was her sense of this, and her conviction that it need not be so, that it could be changed by willpower. That gave her the strength to surmount the formidable political hurdles she faced at the outset, not least through lack of support in her own Conservative Party, in the Cabinet above all, and among the ranks of grandees preferring corporatist compromise. She marginalised them and changed the party into a populist one, a vehicle for the aspirations of second-hand car dealers in Basildon, the sort of constituency that helped to supply her enormous parliamentary majorities.
She also changed the Labour Party, which came to realise that suburban Basildon was now more representative of Britain than the former industrial heartlands of Barnsley or Bathgate. She appealed to this new populist constituency because she was the one that liberated it.
The Britain she took over in 1979 was a Britain not only of the welfare state but also of the nanny state, that tried to do too much for people and so stopped them doing what they wanted to do for themselves, not least by taking too much of their money from them in taxes.
The dead weight of consensus was reinforced by privileges for the public sector and the trade unions. Maggie simply overthrew this structure, unleashing a long if unstable boom that did not finally grind to a halt for three decades.
She also showed that a country successful at home is more likely to be successful abroad, something vital for Britain with its inescapable imperial legacy that is also the foundation for its role in the global economy. But her international success was still more political than economic. By her personal friendships with Ronald Reagan and Mikhail Gorbachev, she eased the end of the Cold War and helped to usher in a new era of world history, the nature of which is not yet clear.
At least we know it will be a capitalist and not a communist era, where the dangers will come from too much freedom rather than too much tyranny.
On the other hand, for those that loathed Maggie, the constructive sides of this career were as nothing compared to the destructive sides. For all its faults, postwar Britain had managed one major achievement, the creation of the welfare state, and she succeeded to a large extent in destroying it, if not on purpose then certainly as the by-product of other aims.
Her obsession with pennywise housekeeping, in public policy known as monetarism, starved a whole range of services that could only survive on adequate public investment. So those services, from health to education to transport, decayed in quality. The sufferers were the millions who could otherwise not afford to buy the services for themselves. Britain, a society of solidarity since the war, became a society of conflict.
The social indictment went further. As for leadership in public life, she turfed out the kindly old toffs, and let the wide boys in. Well-groomed self-made men were her ideal, with few questions asked about their origins or the means by which they had enriched themselves. Often, that was in the City of London, which she also reformed so as to do away with the gentlemanly capitalism of yesteryear.
The City then boomed, to become by far the biggest and most dynamic force in the British economy, totally eclipsing the industrial sector (which continued to decline). Now, apparently, the rest of the country existed just to support this one corner of it where the wide boys had been handed a licence to print money. They spent it too, on conspicuous consumption. The gap between the rich and the poor yawned. The poor rioted. The gap between the North and the South yawned. Scotland drew its own conclusions.
The dangerously heady delights of Thatcherism showed themselves in foreign policy, too. Now came the Falklands War in 1982, the prelude in subsequent decades to further wars in distant parts of the world where direct national interests were hard to see. Instead, the British identification with US global strategy became total. At the same time, the peaceful aim of European integration was treated with scorn and contempt, indeed hindered at every opportunity. The Americans turned out not always as grateful as they might have been, while the French and Germans more or less gave up on us.
We see that love or loathing of Margaret Thatcher can be alike founded in fact, yet points of agreement remain absent.
That is why the British people argued passionately about her while she was in power, still argued passionately about her up to her death and can be expected to go on arguing passionately about her into the future.
It is a measure of her stature that we cannot see eye to eye about her now and probably never will.
Meanwhile, there has been time enough since she lost power to make at least some tentative assessments of what in her legacy is permanent and what is impermanent. Despite the nostalgia in some quarters, it is hard to see Britain ever returning to corporatism and the welfare state. The chance could have come in 1997, but New Labour spurned it to carry on with the essence of Thatcherite social and economic policy, if in less strident guise. New Labour also carried on in close identification with American foreign policy, again in the absence of any marked enthusiasm for it in the British population. Perhaps both these aspects of UK policy have become necessities: if so, it was Mrs Thatcher that made them necessities.
But for the rest, the outlook remains blurred. After the credit crunch of 2008, it is clearly advisable for Britain to find other ways of making its living than through finance, though it is not at all obvious what these might be. Our detachment from the European Union of which we are supposed to be a member increases rather than diminishes. The National Health Service still has not been satisfactorily reformed. Whether the UK will even hold together is far from clear. All these unresolved possibilities had their origins in the time of Mrs Thatcher. But perhaps this is the true measure of political greatness: not to close things down but to open things up, to the people and to the future.
• Michael Fry is a historian and author.