Boris Johnson has mugged and gurned his way into Number Ten, through a leadership contest with a virtually preordained conclusion. It is hard to imagine how he could have lost – perhaps a hostage video with the queen in a grimy basement would have swung the needle away from him a few points – but harder still to imagine how he might govern.

Energy and optimism have been the watchwords of Johnson’s press ambassadors since his victory was announced; the man himself continues to duck press scrutiny. The stress on sunshine and optimism makes Tory politicians and hangers-on sound improbably like wide-eyed Californian acolytes of The Secret, but without any solution to the problems that felled Theresa May it is hardly surprising that his defenders fall back on voluntaristic brio. The parliamentary arithmetic, edging closer to gridlock with the coming Radnor by-election; the restive Europhobe backbenches, and the few increasingly desperate anti-No Dealers; a frustrated and impatient European Commission; the electoral stormclouds of Farage’s Brexit Party; the number of political fortunes now pinned to the promised 31 October deadline – all are to be solved by smiling.

High office has spared us Johnson’s long-threatened book on Shakespeare, but there are those who hope that he will emulate Prince Hal, turning away from his former self and former friends alike. Johnson’s mercurial personality and opportunistic revisions of principle have sustained this hope, which in its most sunny mode envisions him passing a rebadged version of May’s withdrawal agreement – perhaps with a few cosmetic changes to the political declaration; maybe with Labour backing, possibly secured by a second referendum. But as those clauses pile up, the likelihood of such an outcome recedes. It would split the Conservatives, cement the Brexit Party’s support, and permanently tarnish Johnson’s reputation even among his most ardent backers. Hope for this scenario can only be sustained by a double fantasy: that the alchemy of rule will transform Johnsonian lead into civic-minded gold, and that it is possible to return to the Tory status quo ante, when cavilling about Europe was balanced by tacit acceptance of its economic order. That time is past.

Better indicators are Johnson’s record as London mayor and the emerging shape of his political team. He saw himself running London like the chairman of a company, with the day-to-day responsibility (all that noisome detail) in the hands of officials. He is unlikely to repeat that – it was a recipe for bureaucratic infighting, solved only when he was forced to take responsibility for his own office – but he will rely on his officials to shape his strategy. The appointment of Dominic Cummings, the abrasive former Vote Leave director once called a ‘career psychopath’ by David Cameron, as his senior adviser suggests the direction he will take on three key matters.

First, Johnson intends to meet the 31 October Brexit deadline, accepts No Deal as a real possibility, and regards Cummings’s belligerent loathing of both the European Commission and the Shire fantasists of the ERG as aids to that end. Unlike the ERG, Cummings is not a No Deal enthusiast, but he regards threat, tension and brinksmanship as the means to extract both a better offer from the EU27 and compliance from the backbenches.

Second, Johnson intends no truce with MPs over their attempts to assert procedural power in the Commons: recently found in contempt of Parliament, Cummings spat and sneered whenever he deigned to appear in front of a select committee. He despises Westminster’s slowness.

Third, Cummings hates the Civil Service, which he regards as an archaic drag on modernisation. When Johnson came to power in London, he promised to ‘euthanise … dogs in the manger’, Livingstone staffers committed to a different idea of the city. Cummings will be enthusiastic for a similar operation on Whitehall.

Johnson is keen to stress he has an agenda beyond Brexit, claiming he intends to spend on policing and education, and reckon with the crisis in social care. It isn’t unusual for incoming Tory prime ministers to stress their social credentials: May spoke of ‘burning injustices’ on the doorstep of Number Ten, and they burn still at her departure. On social care, Johnson’s camp has already mooted an extra tax on the over-forties, an idea alarming both to Conservatives, suspicious of tax rises in general and in particular when they burden Tory voters, and to those on the left who distrust anything that looks like a move away from universal provision. There are further reasons to be sceptical: Brexit is likely to swallow legislative time for the foreseeable future, and the fractiousness it produces is unlikely to provide clement political weather for major new policy.

As for Johnson’s Cabinet, widely touted as a Vote Leave ministry, it also marks the ascent of the authors of Britannia Unchained, a 2012 pamphlet that derides British workers as indigent and lazy compared to their Asian counterparts, and recommends a slash-and-burn approach to workers’ rights in order to free Britain from its shackles of red tape. Its authors include the new foreign secretary, Dominic Raab, and the new home secretary, Priti Patel, last booted from the political frontline for conducting her own independent foreign policy. Sajid Javid, the new chancellor, is ideologically aligned with them.

Their revivalist Thatcherism combines well with Johnson’s only consistent political position: a dislike of taxation and agitation for the abolition of the top tax bracket. He was the only senior politician to defend bankers after the 2008 financial crisis, and his scattershot campaign pledges about fibre broadband, ‘free ports’, regulatory bonfires and the abolition of ‘sin taxes’ are all patterned according to this right-libertarian weft. Beyond his stock of character flaws or woeful indolence, his policy background ought to be fertile ground for his opponents.

From Brexit to domestic policy, a cloud of illegitimacy hangs over Downing Street. Johnson takes office on the back of an election in which 0.2 per cent of the population could vote, at the end of an abnormally long parliamentary session, with a legislative programme he has no intention of fulfilling, and a manifesto long since binned. He knows that a new session in Parliament would require him to test the confidence of the House, with a serious risk of his ministry collapsing over Brexit policy. He attacked Gordon Brown for not holding a general election after assuming office in 2007; a petty Caesarism that attempted to stretch out a parliamentary session on the edge of expiry as a way of dodging the House’s verdict would far outstrip Brown in arrogance and contempt. But it reveals the uncomfortable truth beneath the ersatz sunshine and wishful thinking: Johnson’s party is fractured, his options are few, and his hand is weak.