Last month I had an abrupt conversation with a leftwinger I know about the result of this year’s general election and what would follow. A northerner, she works for the NHS and has a usually unshakeable contempt for the Conservatives. I was talking optimistically about their skimpy 36.9% share of the vote, and how it did not really constitute an electoral mandate, when she cut me off: “Look Andy, they won.” A few minutes later she mentioned that many of her colleagues were planning to leave the NHS and take their expertise private. She said she might do likewise.

One crucial sign of the success, or otherwise, of this Conservative government will be the accommodations people on the left make with it. For much of 2010 to 2015 the coalition seemed too fragile for many non-Tories to see its radical shrinking of the state as permanent. There was a widespread sense of people holding their breath until the coalition’s inevitable disintegration. But this May’s Conservative win, and the seemingly strong chance they have of another in 2020 – with the Fixed-term Parliaments Act and the coming review of constituency boundaries helping to entrench them in power – mean that over the next decade leftwing Britons will have to choose between rejecting and accepting a new political, economic and social landscape.

The first, most obvious demonstration of that choice will be the result next month of the Labour leadership ballot, and whether Jeremy Corbyn wins as expected. But given the lack of support for him among Labour MPs, a Corbyn victory is unlikely to settle attitudes to the new Tory hegemony even within the parliamentary Labour party. Across the left as a whole, moreover, those attitudes may determine how easily the Tories govern; how long they ultimately stay in office; and what happens afterwards – how much of the current Conservative revolution is left intact by a post-Tory government, however hard such a thing is to imagine now.

We have been down this road before. For much of Margaret Thatcher’s first, 1979-83 government, commentators vied to dismiss its ambitious fusion of icy economics and airy social optimism as a doomed experiment. The revered Anglo-German sociologist Ralf Dahrendorf declared in his book and BBC television series On Britain that Thatcher’s administration, like Edward Heath’s in the early 1970s, had been an attempt “to transform a solidarity society into one of individual competition … Both failed”.

Yet unnoticed by such political obituarists, Britons far outside the usual Tory circles were becoming Thatcherites or Thatcher beneficiaries, consciously or not. The Maggie-mockers of Spitting Image Productions, many of them lefties, used the enterprise zone the Thatcher government had created in London’s Docklands, with its deliberately relaxed health and safety laws, to make their latex puppets out of dangerous chemicals. The Sheffield musician and declared Tony Benn supporter Martyn Ware of Heaven 17 told the New Musical Express in 1982 that “the best and least hypocritical” way to behave as a band was “to act as a business”.

It has been written out of history – but Britons far outside usual Tory circles became Thatcherites, consciously or not

Once the Conservatives’ huge election victories in 1983 and 1987 had made the pervasiveness of Thatcherite ideas unmistakable, the other parties adjusted accordingly. Labour under Neil Kinnock and Tony Blair, the SDP under David Owen, the Liberal Democrats under Nick Clegg – for a quarter of a century until the financial crisis of 2008, British politics was full of left-of-centre figures accepting weaker trade unions, broader property ownership and a stronger free market. In 1993 even Thatcher’s old “enemy within” Arthur Scargill – then still leader of the National Union of Mineworkers – tried to buy a council flat using her right-to-buy legislation.

You can call such behaviour hypocrisy, or an adjustment to new realities. Either way, much of this response to Thatcherism – like the wider ambivalence of millions of Britons towards her reforms – has been written out of history. When she died in 2013 almost all the coverage assumed that every Briton was either a devotee or her mortal enemy. Yet it was the gradual, often partial, usually permanent conversion of voters and opponents, as much as her much more famous victories over Scargill or the Argentinians, that gave her government its rare importance.

It is a bit early to award David Cameron the same world-changing status. His governments have been complacent and slapdash – see the “reformed” benefits claimants crudely invented by the Department of Work and Pensions and exposed this month – as often as they have been zeitgeist-altering. Meanwhile, his reliance on old Thatcherite policy ideas such as privatisation and the right to buy doesn’t suggest his administration is going to become the sort of fresh intellectual or ideological project that many non-Tories will fall for. If the Conservatives stay in power for a long time, their offer to voters will get very stale.

Yet fixed-term parliaments give their rule a sense of permanence that Thatcher’s never quite had. Even with her far more robust Commons majorities, her administrations felt fragile whenever there was a big crisis – such as the Falklands invasion or the spectacular cabinet falling-out over Westland Helicopters. The current Tory government can have few such fears of overnight collapse. Its almost guaranteed five-year term helps explain the readiness of Labour council leaders to sign up to chancellor George Osborne’s notion of a northern powerhouse, despite its sketchiness and his reputation for doing everything for a party-political purpose. For the foreseeable future, in the scattered parts of Britain where the left still holds power, grabbing the biggest piece you can of the shrinking Whitehall pie may seem the only game in town.

There is something of the GLC’s rebelliousness and contempt for conventional political wisdom in Corbyn’s campaign

Or the left can play another one. In the 80s there was one conspicuous exception to all the leftists crushed or seduced by Thatcherism. Ken Livingstone’s Greater London Council was over-ambitious, often unpopular, and sometimes chaotic; but between 1981 and 1986 it began to build a new version of British socialism that took account of the capital and the country’s increasing diversity, and of the energies of community politics and even capitalism itself. The “Red Ken” GLC offered a modern alternative to Thatcherism – or at least a defiant island of opposition.

There is something of the GLC’s rebelliousness and contempt for conventional political wisdom in Corbyn’s campaign for the Labour leadership. Like Livingstone in the early 80s – whom Hugo Young, later of this newspaper, then considered a future Labour leader – Corbyn argues that compromising with the Conservative government and the Conservative discourse will only make them more dominant. He may well be right. For all Tony Blair’s electoral triumphs, his acceptance of much of Thatcherism meant that when New Labour fell, the Tories could easily resume her work.

Then again, the Livingstone GLC did not end well: the Conservatives simply abolished it. In rightwing times the British establishment is even less tolerant than usual of leftwingers who won’t give ground. Defying Cameron and his successors for the next five or 10 or even 15 years is going to take a British left with bloody-mindedness, attractive ideas and luck. Does such a left still exist? We’ll find out.