Boris Johnson uses today's Telegraph to trail what will doubtless become a leadership bid, and his agenda for post-referendum Britain contains some remarkable claims. Not in the form of proposals, but by its lack of them. If Johnson has his way, Brexit is going to involve inactivity on an industrial scale. He envisions a 'balanced and humane points-based' immigration system, but that’s for the extremely indeterminate future – and everyone can meanwhile look forward to 'intense and intensifying' co-operation with Europe, and opportunities to live, travel, work and study on the continent just as they please. British businesses will enjoy uninterrupted 'access to the single market'. The only apparent change, which will happen 'in no great rush', will be the UK's 'extrication' from the European Union's 'extraordinary and opaque system of legislation: the vast and growing corpus of law enacted by a European Court of Justice from which there can be no appeal’.

The programme sounds so laid back that it's tempting to wonder why we committed national hara-kiri in the first place. But Johnson’s proposals obscure a lunge for power as disingenuous as it is opportunistic. The only pledge that's even arguably within his power to achieve is a points-based immigration system, and we've had one of those since 2008. Every other European activity he promises to preserve, from residential rights to the single market, will have to be the subject of fraught negotiations; and the legal measure he mentions, apparently based on a blog post written by his wife a couple of months ago, demands constitutional unravelling on a scale that would keep lawyers and civil servants in lucrative employment for decades to come.

Johnson knows all this. As a few sceptics have already observed, he almost certainly hoped to lose the referendum by a whisker, which would have left him perfectly positioned to snipe at David Cameron, but spared the tedious business of actually amputating the United Kingdom from Europe. The plan went awry, because he’s too natural a demagogue: like Jeremy Corbyn’s charismatic twin, he put his case too irrepressibly to attain the precise balance between plausibility and unpopularity that heroic failure would have required. Now that he unexpectedly finds himself at Downing Street's threshold as a consequence, he needs to buy time – and his meaningless manifesto in the Telegraph is designed to do just that.

Worried Remainers might take comfort from this, especially because almost everyone who knows Johnson attests to his many liberal and Europhiliac instincts. The problem is that his gamble for the sake of personal ambition has raised the stakes far higher than he could ever have anticipated. On the day in February when Johnson chose to throw in his lot with Michael Gove rather than David Cameron – a decision he said was taken after veering between the two sides 'like a shopping trolley' – a poll gave supporters of the EU a 15 per cent lead. Had Johnson campaigned with less panache, Brexit would probably have fallen short of a majority; and if he had plumped for Remain in the first place, the UK would almost certainly still have a future in the EU.

The political achievement implied by that observation carries a concomitant responsibility. The Vote Leave team achieved its victory by inflating expectations wherever potential votes could be found: not just with its implied promise of £350 million more to spend on the NHS each week, but also by feeding fantasies of sealed borders and immigrant repatriation that anyone non-white who came of age in the 1970s knows to recognise with cold fear. Over the last few days, supporters of Brexit have tended to dismiss these concerns – and the multiplying reports of racist incidents on social media – as the bleating of anti-democratic sore losers. But Johnson is probably not among them, and his insistence in the Telegraph that the referendum result was inspired by a belief in democracy rather than anti-immigrant sentiment reflects his hope of taming the dangers that he has helped loose. Unfortunately, it is very probably too late.

I distinctly remember Johnson’s self-deprecating response when a friend we have in common congratulated him on his appointment as editor of the Spectator in 1999. Paraphrasing Keats’s epitaph, he mumbled that fame meant nothing because all lives are 'writ in water'. I find it as impossible now as I did then to gauge how he squared that sentiment with his ego. Against recent events, however, the words have assumed a peculiar truth. Upheavals frequently throw up trailblazers – Jean-Sylvain Bailly in revolutionary Paris, Alexander Kerensky in pre-Bolshevik Moscow, Shapour Bakhtiar in Iran in 1979 – who are swept aside by the causes they championed. Such parallels probably appeal to Johnson’s sense of self, but he has personally unleashed nationalist forces that won’t be restrained any time soon. It remains to be seen if he will ride the beast or be devoured by it – but whatever happens, it isn’t going to be pretty.