Beneath the surface disorder of modern British politics, there are steadier patterns to be found. One of them is so regular, and so central to the workings of the whole system, that it’s rarely noticed, let alone challenged.

This pattern is hugely to the advantage of the Conservatives. Here’s how it works. When the Tories are in power, as they have been for 27 of the last 40 years, they often struggle to govern effectively. An election follows. The Tories run a negative campaign, drawing attention away from their own failures and ineptitude to the potential problems of a Labour government. To the surprise of some, the Tories win: either decisively or just well enough to stay in office. They announce that they will govern differently this time. Much of the media believes them. The Tories struggle in government once again.

Faith in their credentials helps win tight elections. That they always find a way to rule is a self-fulfilling prophecy

Boris Johnson has already been through all these stages except the last one – and with a large majority, the temporary momentum that always follows a Queen’s speech and the UK’s scheduled exit from the EU next month to dangle before their supporters, the Conservatives will probably be able to enjoy promising things, rather than having to deliver them, for a while yet. This is Johnson’s favourite and most effective political mode. “Government will now engage flat-out on a programme of change for the better,” he pledged, with characteristic energy and vagueness, during the debate on the Queen’s speech. “A new golden age for this United Kingdom is now within reach.”

In one sense, the Tories have earned this easy phase with their handsome election victory. In a democracy, why shouldn’t a re-elected government enjoy a honeymoon, when journalists and voters give them the benefit of the doubt ? Yet the credulity with which the promises of this and other returning Conservative administrations have been greeted, often by commentators who only weeks earlier were castigating the same ministers for their incompetence, suggests something more political is going on. There is damaging deference towards them – an unstated but widely held assumption that they shouldn’t be judged too exactingly by their record in office.

The Labour party receives the opposite treatment. Even mistakes it made in government decades ago, in an entirely different political and economic context – such as failing to control the then powerful unions during the winter of discontent – are widely taken as warnings about how it would govern next time.

Sometimes, the deference shown towards the Tories comes from left-of-centre journalists and reflects a pessimism that the Tories are, despite all their flaws, Britain’s natural ruling class. And sometimes it comes from the right and reflects an optimism that the Tories, however often they have disappointed and compromised in the past, always have the potential to rediscover their true path. “Politics has been transformed in a week,” declared the Daily Telegraph giddily after the election. “Suddenly they seem like a whole new party.”

Either way, the media’s impulse to take incoming Tory premiers at their word echoes the inclination of many voters to trust Tory governments to be financially prudent, streetwise on foreign policy, and generally competent and stable – despite all evidence to the contrary. This misplaced confidence is particularly helpful to the current, broad-brush generation of Conservative politicians, who are better at rhetoric and election slogans than the detailed, patient work of improving the economy or the state.

This faith in the Conservatives’ governing credentials helps them win tight elections. The idea that they will always find new ways to rule becomes a self-fulfilling prophecy.

Yet many Tories who have actually been in government are much less sure about their party’s aptitude for it. The memoirs of even the most confident and successful Conservative figures, such as Margaret Thatcher, are riddled with moments of self-doubt, frustration and sometimes outright panic while in office. John Hoskyns, a radical early Thatcherite who was the first head of her Downing Street policy unit, described the experience of government as like “trying to pitch a tent in the middle of a landslide”.

But reviewers of such books tend to focus on the anecdotes about backstabbing and leadership coups – material suggesting that while the Conservatives might be a nasty lot, they are also assertive and pragmatic. Meanwhile, serialisations in the rightwing press are little more than descriptions of Tory triumphs. Thus the party’s aura of invincibility remains intact.

This overestimation of the Conservatives’ capabilities is especially galling now, when we have a prime minister whose record of keeping promises and enacting major reforms is almost nonexistent. As mayor of London from 2008 to 2016, Johnson neglected the capital’s acute housing and air-quality crises, in favour of a little-used cable car across the Thames and the unbuilt airport scheme, “Boris island”. As foreign secretary from 2016 to 2018, he was widely considered one of the most clumsy and ineffective ever to hold office. And as prime minister so far, for all his electoral success, he has seemed just as casual about the business of government, giving vague, incoherent speeches, and sometimes appearing unable to understand or explain his own policies.

With its lurch to the right, Britain is no longer special in Europe | Stefan Bielik Read more

This is the premier who is now expected to solve two huge problems: implementing Brexit and reviving swathes of northern England that have been declining for decades, and where the Tories have not, until now, been popular for almost a century. Meanwhile the government’s finances are deteriorating, Britain’s economic growth is slowing and a recession may be imminent. It could be the hardest set of challenges faced by a new government since the 70s.

Johnson may learn to be more conscientious. Unexpected talents may emerge from a cabinet seemingly made up of fanatics and chancers. Dominic Cummings may metamorphose from a sly campaign strategist into someone who can reinvent the British state.

But don’t hold your breath. Only three years ago, in her first speech as prime minister, Theresa May promised “to make Britain a country that works for everyone”, almost exactly as Johnson is doing now. Then as now, many observers thought they saw a potent new Conservatism crystallising. But it was a mirage.

In truth, the Tories find governing grumpy old Britain – let alone reforming it – as difficult as Labour do. But if we don’t stop being mesmerised by them, they will carry on ruling us most of the time. And perhaps we’ll deserve it.

• Andy Beckett is a Guardian columnist and author of Promised You a Miracle: Why 1980-82 Made Modern Britain