On 15 January 2009, shortly after take off from New York, US Airways flight 1549 hit a flock of Canada geese. Birds were sucked into the jet engines, both of which failed. There was no prospect of reaching a runway, so the captain glided on to the Hudson river, saving everyone onboard. This feat is now the subject of a Hollywood film, starring Tom Hanks as the heroic pilot.

Instinct tells us that the passengers were lucky that day: lucky to have such a skilled crew, lucky to be alive. But in an important way they were also very unlucky. In statistical terms, the loss of two engines to a bird strike is highly improbable. People who board planes do not usually come so close to death.

Evaluation of what makes a fortunate situation depends on the time frame in which events are observed. Unforeseen danger triggers one set of perceptions that can be overridden only by a happy ending – which brings us to Britain’s Brexit flight into the unknown.

May wants to make nice with Trump, because that is what prime ministers do with presidents

The chancellor, Phillip Hammond, is at the controls of an economy with warning lights flashing. Debt levels and the deficit are too high. The drop in the value of the pound heralds a likely increase in inflation. Independent forecasts project slowing growth and disappointing revenue, attributed in part to uncertainty over future relations with the European Union. Business passengers send messages of anxiety to the cockpit about the plane’s trajectory.

So Hammond sees his autumn statement as an exercise in caution. Anticipating turbulence, and with poor visibility, the chancellor tells us to keep safety belts fastened. It is too early to say whether or not this is the opening scene of a disaster movie.

Many Conservative MPs find Hammond’s attitude frustrating. They mutter in private that he is indulging the pessimism of a remainer revanche. The Brexit radicals see a different economy: growth sustained, a devalued currency helping exporters, low unemployment, high consumer confidence. They want the chancellor to sound more exuberant, celebrating the bounty that awaits Britain once it is liberated from continental shackles.

With so much unknown about the destination, interpretation of Britain’s prospects is largely a matter of prior conviction. The more ardent someone’s desire for Brexit before 23 June, the likelier they are to believe that downsides are now exaggerated by Europhile scaredy-cats. This is a function of temperament and appetite for danger as much as rational judgment. Leave campaigners all knew that success in the referendum would deliver a massive shock, but they were divided about how honest to be about that prospect. The most ideological Brexiters relished a bit of destruction in the belief that it contained creative properties. There could be no free-trading phoenix without reducing existing structures to ashes. But there was a risk that voters would recoil from a flame-throwing manifesto.

That tension endures for the Tories, in the problem they now have with Nigel Farage, arsonist-in-chief of the old order. Many imagined that Ukip would be rendered obsolete by the accomplishment of its Eurosceptic mission. Farage was viewed by liberal-minded leavers as a liability or a useful idiot whose rowdy, anti-immigrant populism was a short-term expedient for mobilising parts of the electorate. He was to deliver votes, then disappear.

Photograph: Carl Court/PA

That looked naive even before Donald Trump’s election victory in the US. Now those same Tories see the president-elect treating the acting Ukip leader as a chum. Trump told his Twitter followers on Monday that Farage would do a “great job” as UK ambassador to Washington – a role for which there is no vacancy. If there were, Farage would come somewhere below Larry the Downing Street cat on Theresa May’s list of suitable candidates, although she daren’t say so.

May wants to make nice with Trump because that is what prime ministers do with presidents, and because a favourable deal with the US is a vital component in the plan for post-EU trade. Trump’s intervention is a breach of all diplomatic protocol, but there is no point complaining about that. Reckless transgression is his modus operandi. May had better get used to it. Farage, meanwhile, revels in the attention bestowed on him from across the Atlantic and the discord it has sown in the Conservative party, where opinion is divided between those who see any line into the new president as a channel to keep open, and those who wish the prime minister could find a way to wipe the grin off the face of their old Ukip nemesis. Less gung-ho Brexiters are disappointed that May has not crushed the idea of giving Farage a peerage.

That there is political kinship between Trumpism and Ukip is beyond doubt. The dilemma facing the Tories is that they want to advertise the economic opportunities in a Trump presidency – the message repeated by Boris Johnson – without admitting that Brexit shares much ideological DNA with an ugly breed of nationalism. So Johnson and others pretend that Trump is an orthodox Republican with bad manners, not a reckless demagogue who threatens to destabilise the world order.

Farage won’t let them get away with that. He wants a piece of the revolution he helped create, and he is running rings around the moderate Brexiters to get one. Who is useful and who is the idiot in this new scheme of things?

Farage is a survivor. During the 2010 general election, he hired a plane for a campaign stunt and it nosedived into a field. He was lucky then and his luck has not run out. He has hapless enemies at home and a powerful new friend abroad. Those liberal Brexiters who thought his time was up after the referendum are disoriented. They should be worried. They chartered this flight. They cheered on take-off, anticipating that after a bumpy ascent through the clouds, blue skies would appear. They trusted May and Hammond as experienced pilots.

Now the horizon has darkened. The engines have fallen quiet. Nerves fray. So the Tories call out to the cockpit for more thrust, more confidence, more optimism. Then a voice comes over the Tannoy that doesn’t belong to the prime minister or the chancellor. It’s Donald, speaking with his flight attendant, Nigel, and they are promising a very different kind of ride.