No 10 hopes it can find a way to instil some discipline into the Great Disruptor during his visit

Sandwiched between the psychodrama of his confrontation with his Nato allies, and the amour of his summit with Vladimir Putin in Helsinki, there was a chance that Donald Trump, a president who thrives on controversy, might treat his interlude in England and Scotland with indifference.

UK on different route to Brexit than people expected, Trump says Read more

At one level, a visit bordering on the normal would be mission accomplished for Downing Street, but at another, this visit matters far more to the UK than to the president. Britain needs to register with a president so inattentive to America’s historic ties, and above all hope the instincts of a self-confessed “stable genius” do not lead him to trash the Brexit deal that Theresa May is struggling to sell to her party.

Judging by the inferences behind his remarks at his freewheeling press conference in Brussels, Trump is going to struggle to constrain himself. Saying he had been reading a lot about Brexit in recent days, he repeatedly hinted that he thought May was not delivering what the people had voted for in the referendum. He also drew parallels between his own election and Brexit, saying they were both born out of a revolt against migration. The clear implication was that he was the standard bearer for a global populist revolt.

Downing Street can only hope that by the time he holds a joint press conference with Theresa May on Friday they can find a way to instil some discipline into the Great Disruptor.

It will not be for lack of effort. No 10 has done all that it can to make the visit to what he describes as a “hot spot” as Trumpian as possible. Tea with the Queen, a night at the ambassador’s residence overlooking Regent’s Park, a dinner with fellow businessmen in Blenheim Palace, ceaseless rounds of golf, a brief press conference and an even a mini-military display at Sandhurst in a bid to match the pomp of Bastille Day that so impressed the president on his visit to Paris last year. The protests in central London will be safely out of earshot in Chequers, the site of the talks between May and Trump.

Trump claims victory at Nato summit after fresh row over defence spending Read more

Yet Theresa May cannot change her character, including her innate caution. He does not warm to her. She, along with the German chancellor. Angela Merkel, almost personify the qualities he disrespects in foreign leaders.

His refusal on his departure to Europe to endorse her leadership, coupled with his observation that the country she governs was in turmoil, seemed designed to destabilise. The suggestion that he might break diplomatic protocol and see his good friend, the former foreign secretary Boris Johnson, revealed a lot about his personal preferences, as well as the kind of hard Brexit route he would like the UK to take.

The fact that his national security adviser, John Bolton, met the Eurosceptic European Research Group shows the White House is at least open to a British no deal breakout from the EU. Bolton, like his ideological predecessor Steve Bannon, is evangelically hostile to the EU.

As one UK official admitted “the levels of unpredictability are unprecedented. You have to manage this as best you can.”

The best way to respond, the UK argues, is not to construct a narrative about the breakdown of the transatlantic alliance, but instead to compartmentalise, and address Trump by each issue in turn. The meat of the talks will be a discussion about Trump’s approach to trade, including how soon, and on what terms UK could strike a deal with the US once outside the EU.

Although in headline terms the UK appears to lurch confusingly from the front to the back of the queue for a trade deal, Liam Fox’s Department for International Trade is in his fourth round of talks with his US counterparts. A lot of the early ground clearing has been achieved.

But, as former UK ambassador to the US Nigel Sheinwald said, a US-UK trade deal cannot be seen in isolation from the damage Trump is wreaking on the wider trade order. If the UK is to strike wider deals after Brexit, the context required is one of stability, not protectionism.

Inevitably the single most sensitive issue is Russia. May has welcomed the Trump-Putin Helsinki summit, saying “open channels of communication between the US and Russia are a way of reducing risk”.

But the UK, historically and due to the Salisbury nerve agent attack, has been the European country most hostile to Putin. Ministers hope the Chequers talks will reveal what Trump, left alone with Putin in what Trump ominously described as a loose meeting, proposes to achieve.

Ostensibly, the administration policy remains hostile to Russia. It is firm in his opposition to the Russian incursion in Ukraine and Trump expelled an unprecedented 60 diplomats over the Salisbury attack.

Yet there is doubt. The British thought it had persuaded the US to sign up to some strong wording on Russia in the G7 communique in Canada, only for Trump to disown it all in one famous tweet. At Nato Trump hinted that he might accept the Russian occupation of Crimea as a fait accompli, and repeatedly suggested his relations with Putin could change from competitor to friend. He did not rule out ending military exercises in the Baltic states and said he would discuss nuclear disarmament.

British officials are specially concerned about Trump’s plans for the 2,000 US troops still in Syria, and whether Trump will offer to withdraw them without any guarantees either about the withdrawal of Iranian troops inside Syria, or a future constitution for the country.

Above all Downing Street needs the visit to be tangible proof to show that once outside Trump’s hated European Union, Britain will retain one reliable and enduring partner. Unfortunately for May, Trump’s extraordinary threats at Nato and his often contradictory comments, shows how how much risk is involved in dependence on Trump’s America.