James Frayne is Director of communications agency Public First and author of Meet the People, a guide to moving public opinion. The focus of this column is Theresa May’s conservatism for “ordinary working people”.

While it’s reasonable to assume many of the defining characteristics of Britain’s relationship with the US will continue as they always have (like intelligence sharing), Theresa May’s immediate and short-term personal relationship with President Trump really matters. And its importance makes life extremely complicated for May and the British Government generally.

Trump will enter the White House at a crucial time for Britain. Simply put, we need to make rapid progress on the early stages of a trade deal and we need to hear a US commitment to the continued security of Europe. Without the first, Brexit will be more turbulent and complex than it might have been. Without the second, Russia will surely be encouraged to test Europe’s ability and willingness to protect its interests on its eastern frontiers.

But Trump will enter the White House facing huge international scepticism and outright opposition. Some of this opposition would have been there for any Republican President, but this goes well beyond the usual left-leaning activists. And much of it is justified: Trump’s behaviour in the election campaign was often appalling. Ordinary people are worried about who Americans have elected.

America has been able to play a global leadership role because of its massive security apparatus and highly skilled foreign service. But this role was also made possible because of the moral standing of the country. American public diplomacy – propaganda, if you prefer – has generally been effective because it has been able to project moral purpose. Not every administration has been perfect, but every President (bar Nixon, at the end) has been able to credibly play the role of leader of the free world.

Maybe Trump will surprise us and rise to the role he’s been chosen for. His early Cabinet picks give reasons for hope. But it seems very possible that Trump will continue to say and do things that undermine the moral standing of the US and make America’s leadership role much more difficult. In turn, it is possible that many respected figures in American public life, and many in the wider administration, will begin to cast doubt publicly on his fitness for office. This will affect domestic public opinion, regardless of many Americans’ disregard for the opinions of elites and voters elsewhere.

In short, relations with Trump are fraught with risk. Not only will a close personal relationship potentially undermine May and Britain’s position in the wider world but it might not even be beneficial for our future relations with the US. So, how should May approach Trump?

Firstly, she needs to construct a very business-like relationship with him – with meetings dominated by substance and action. Forget cinema nights and casual walks – everything should be done formally (and warmly, of course). Secondly, crucially, May also needs to spread the risk by cultivating close relationships with as many of the other senior administration politicians and officials as possible. Prime Ministers and their staff like to deal with those they see as their peers. On this occasion, May should be more than willing to deal with anyone that can help Britain to achieve its short term trade and security goals and that has a reputation strong enough to deal with whatever Trump does.