The prime minister kept a calculated distance from the US president at the Nato summit because he knows their similarities play badly with voters

A US president’s low-key exit from a Nato summit, skipping the traditional press conference, would once have been perceived as a snub to the host government. But Donald Trump’s departure from London will come as a relief to Boris Johnson. Mr Trump is a fan of Brexit and praises the prime minister as the man to deliver it, but his presence in the country was an electoral hazard for the Conservatives.

Some British voters admire Mr Trump, or find him entertaining, but more do not. It is no recommendation for the Tory leader to be liked by a man notorious for dishonesty, ignorance, narcissism and chauvinism.

The US president did one favour for his British counterpart. He claimed no interest in the NHS as a subject of post-Brexit trade talks. That helped rebut a Labour campaign attack, although the veracity of the denial is as doubtful as everything else Mr Trump says.

The two men keeping a choreographed distance from one another does not dispel the perception of ideological proximity, which is problematic for Mr Johnson on many levels. European governments have largely accepted that Brexit will happen, but that does not mean they are reconciled to its strategic implications. The 2016 referendum and Mr Trump’s election are associated in continental leaders’ minds as twin ballot-box traumas. They appeared to herald a two-pronged assault on institutional framework that has underpinned European peace and prosperity since the second world war.

Mr Trump has been openly contemptuous of EU leaders and engaged them in a destructive tariff war. Mr Johnson was known in Brussels as a propagandising Eurosceptic journalist before he was ever elected as an MP. His reputation for disregarding facts and reckless mischief preceded his arrival in Downing Street. Realpolitik compels continental leaders to do business with both men, but the sense that Britain and the US have been captured by a wrecking political culture has opened dangerous divisions.

This is a bigger problem for Mr Johnson than Mr Trump. The US can afford to rip up the rules of international engagement. It is an unwise path but technically available to a superpower. The UK has no such luxury. A British prime minister who plays Mr Trump’s game exposes the country to dangerous diplomatic isolation and economic decline.

Mr Johnson appears to recognise this hazard. He reassures EU audiences of his support for their common enterprise, while seeking divergence from their regulatory framework. At the Nato summit he has emphasised continuity with the past. He has avoided being drawn on the question of whether Europe should pursue a more autonomous security agenda when Washington might no longer be reliable. That is a strategic conundrum to which Brexit offers no solution. The awkwardness of Mr Johnson’s position has been neatly captured on film. He appears with a group of leaders at a Nato reception, apparently all sharing a joke at Mr Trump’s expense. He later denied any knowledge of the episode.

The Conservatives will be glad if the whole summit is swiftly forgotten. That in itself hints at a wider cultural fraud being perpetrated in this election: the assertion of Brexit as a project of national emancipation when, on the terms currently on offer, it will make Britain more subordinate to US interests and weaker in negotiations with Brussels. Tory discomfort around Mr Trump’s visit flows from widespread British mistrust of the man. That in turn is symptomatic of a cultural similarity with the rest of Europe that is much neglected in political debate. Our attachment to socialised healthcare and suspicion of US opposition to it is emblematic of a gulf between the political traditions on either side of the Atlantic. There is common history, and a common language, but just as many points of divergence.

There is an appetite in Britain to “get Brexit done”, as Mr Johnson glibly promises, but that is a product of fatigue with the process, not a licence to turn the country into a European franchise of Trumpism. Those Conservatives who pursue such an agenda do so surreptitiously, knowing it is not one that appeals to the vast majority of British voters.