Politics​ has never been a pursuit that requires total honesty. Nor, historically, has it been a vocation that scientists or other kinds of expert are drawn to. The New Labour era, which produced an elite career escalator linking university, think tank, ministerial advice, Parliament and finally government, was an anomaly in the longer sweep of things. The reason there are so many mechanisms in place to remind powerful people of the actual facts of matters – mechanisms that include quangos and policy research institutes and publicly funded broadcasters – is that we assume they need constant reminding. A functioning constitution should be able to cope with the odd charlatan and bullshit artist, steering them gently away from the levers of power like a friend removing car keys from a drunk.

When we say that someone is ‘good with words’, we don’t mean they are reliable in how they relate them to things and deeds. On the contrary, the most brilliant rhetoricians or storytellers are those who can conjure an escape from the tedious constraints of the facts or past promises. However much the media pursues the question of Boris Johnson’s ‘character’, we shouldn’t kid ourselves that politics has ever been a truthfulness contest.

How much worse can things get? Quite a bit, it turns out. If politics has always attracted and to some extent rewarded the liar, the effect of Brexit on public life is that there is now a penalty attached to speaking the truth. The Conservative leadership contest is a curious spectator sport (save for the 160,000 electors with Conservative Party membership cards) in which the first contestant to accept reality is the loser. Words have now broken completely free of their factual moorings; Johnson and Jeremy Hunt seem committed to touring the nation and its television studios misreporting and misdescribing the economic, legal and political realities that will confront the next prime minister. To do otherwise would be an act of surrender.

Things have been drifting in this direction since the 2016 referendum campaign, with its infamous lie that ‘we send the EU £350 million a week.’ Hardline Brexiters now revel in their disregard for the statements of experts and fact-checkers, whom they lump together with the BBC, Channel 4, Whitehall and universities as part of a Remain tendency in public life. The beauty of ‘sovereignty’ as a political ideal is its metaphysical character, which evades efforts by economists and civil servants to pin it down, and seems to release political speech from the straitjacket of verifiable evidence.

Whole new vistas of political and cultural possibility seem to open up as a result. The political liar ‘is an actor by nature’, Hannah Arendt said. ‘He says what is not so because he wants things to be different from what they are – that is, he wants to change the world … Our ability to lie – but not necessarily our ability to tell the truth – belongs among the few obvious, demonstrable data that confirm human freedom.’ Freedom is what this is all about. The complaint that ‘you can’t say anything any more’ is often heard as a grudge against ‘political correctness’, but the yearning to be able to say anything can just as easily find expression in support for the leader who will do precisely that, regardless of evidence.

From this perspective, the Remainer fixation on facts appears like a form of verbal constipation, to which Johnson’s gleeful freewheeling serves as the remedy. Note that the quality Johnson’s fans most applaud in him is cheerfulness, something Theresa May was never going to offer, suggesting that she may have missed the point of Brexit all along. The summer has taken on a carnivalesque quality; normal constraints around public speech have been suspended for the duration of a truth jubilee. For Johnson and his fans, this may be as good as it gets.

As this ‘cheerfulness’ is ratcheted up, the freedom to ‘say anything’ starts to engulf an expanding array of policy domains. With the leadership contest entering its final weeks, the same can-say attitude has been directed towards fiscal policy. Johnson and Hunt are now offering tax cuts and public spending increases which, by any account, would add tens of billions to the annual deficit (Labour claims that Johnson’s plans would add £57 billion, Hunt’s £43 billion) – when the vital necessity of reducing the deficit had previously been the Conservative justification for austerity.

Johnson has promised to end public-sector pay freezes. To get Britain through a ‘no deal’ scenario, Hunt is invoking a positively Rooseveltian fiscal spirit, tweeting: ‘We spent just over £1 trillion bailing out the banks after the financial crisis. So if we did it for the bankers then why wouldn’t we now do what is needed for our fishermen and our farmers?’ Never one to be outdone in rhetorical hyperbole, Nigel Farage has started fleshing out a Brexit Party policy programme with a promise of £200 billion (more than the entire budget of the NHS and schools put together) to be invested in non-London regions.

An interesting subplot in this festival of Keynesian ideas is the status of broadband access. One of Johnson’s first policy announcements was to offer ‘full fibre to every home in the land’ by 2025, which civil engineers consider utterly unrealistic (the government’s current ‘aspiration’ to deliver it by 2033 is very optimistic). Farage has also fixated on faster broadband nationwide, plus free and fast wifi on buses and trains outside London. There was a time when the internet was identified with the ‘global village’ and hipster startup culture; now it has become a key symbol and rallying point of non-metropolitan nationhood. The Farage-Johnson fantasy, it seems, is to weaken the cultural power of the large cities and university towns (those splodges of Remain on the Brexit map of England), and with it the influence of the BBC and Channel 4. Who really needs public service broadcasters in this high-speed internet future? Let a million YouTube channels bloom.

Loose talk is infectious and addictive. It begins with a dodgy claim on the side of a bus, and before you know it you’ve promised a spending spree so lavish that John McDonnell is accusing you of being ‘reckless’. But something significant has happened along the way that may cause particular concern to traditional Conservative sympathisers in the business and financial sectors. The claim that politicians are ‘liars’ can encompass two quite different kinds of lie. The first concerns facts – that is, things that have verifiably happened in the past. The ‘£350 million’ was this kind of lie: it excluded the money Britain had received back every week. It is this kind of lying that Donald Trump engages in compulsively, denying the public record, disowning past statements. It consists in a refusal to be bound by empirical data or by witnesses.

The second concerns broken promises, which is what many assume will happen once Johnson or Hunt enters Downing Street and is finally confronted by the realities of Brussels and Treasury bureaucracy. But until that future arrives, promises aren’t really lies so much as dubious pledges. What’s happened to British politics over the past three years is that, on discovering that it’s possible to lie about the past and get away with it, Conservatives now speak about the future as if there won’t really be one. Dishonesty about facts bleeds into dishonesty about intentions and prospects.

One might imagine that the first type of lie – the Trumpian one – is the more egregious. After all, if it’s an established fact that Europe’s trade surplus with the US is $101 billion, it’s surely monstrous to claim that it’s $151 billion. Such mendacity does a fundamental violence to the relationship between language and the world. But business and financial interests have often been far more worried by the second type of dishonesty, the failure to keep one’s word. Frankly, investors don’t really care about lies plastered on buses or asserted about the size of the crowd at an inauguration. If the next prime minister insists that the global climate cooled down in 2018 or that the European Union banned bendy bananas, it’s of no great concern to the CBI. It is when politicians start to talk big about the future that financiers get antsy.

Because investment is a future-oriented activity, one of the main threats that democracy poses to capitalism is that cast-iron policies, promises and rules can be tossed aside at any moment. It isn’t just voters who worry about politicians’ honesty: businesses worry that political words deployed as mere rhetoric, to win favour in the short term, can never reliably operate as a constraint. This problem has been especially acute in the era of neoliberal globalisation that emerged after the 1970s, as nation-states have constantly sought to reassure international investors that they will stick to predictable regulatory, monetary and fiscal frameworks. Various instruments have been invented to achieve this, from central bank independence, which removes monetary policy from the domain of democratic politics, to the ‘stability and growth pact’ that has limited European Union member states’ fiscal freedoms since 1999, to Gordon Brown’s self-imposed ‘Golden Rule’, which stipulated public borrowing limits.

Business investors can cope with various models of capitalism, involving a wide range of tax rates, corporate governance systems and regulatory frameworks. What they can’t cope with is perpetual uncertainty. When political promises no longer hold their value over time, the value of a nation’s money will eventually suffer the same fate: inflation and devaluation are the consequence. (At its simplest, the neoliberal diagnosis of 1970s inflation was that too much democracy had led politicians and employers to make more promises than they were economically capable of honouring.) Contrary to everything George Osborne led us to believe, it isn’t deficit spending as such that threatens economic stability: it’s the fact that Johnson’s words offer scarcely any clue as to what he plans to do.

If the Conservative Party is about to draw a line under the era of austerity in such exuberant fashion it ought to be surprising. Then again, the right has often been less neurotic about prudence than the left (especially in the US); the right knows, after all, that it doesn’t have to work as hard as the left to win the trust of capital. But in the present atmosphere, few of Johnson or Hunt’s pledges seem likely to survive very far into the autumn. Spending commitments are being let off like fireworks, lighting up the night sky for the immediate pleasure of the 160,000 voters. Compared to Johnson’s ‘do or die’ promise to depart the EU on 31 October regardless of whether a deal is in place, pledging a few billion here and there is just noise.

But all this does pose worrying questions about what kind of democratic government will exist once the UK has got through the next six months of uncertainty. Who or what will voters and businesses be placing their trust in when political speech has finally been reconfigured as mere mood music, to be used to soothe or excite, but never to constrain? Politics could become riven by a kind of ‘front-stage/back-stage’ duality, fronted by ‘cheerful’ figures speaking the language of sovereignty, while brushing aside the details of policy and spending for others to deal with. Like the reality of austerity, the reality of Brexit will become visible at some stage. But who’s to say that its cheerleaders will be prepared to recognise it as such?