Relations between Britain and the United States have rarely been described as simple, but they have long been called special. Yet in recent days that relationship has come under strain, after a sharp exchange between Donald Trump and Keir Starmer over the latest international crisis and Britain’s response to it. For more than eighty years the United Kingdom has defined its place in the world partly through its alliance with the United States. But moments like this raise uncomfortable questions about how Britain should act amid a shifting global order.

Some argue that foreign policy must ultimately be guided by national interest. In an uncertain world, they say, Britain cannot afford to jeopardise its most important alliance. Presidents come and go, but the strategic relationship between the two countries endures. In that view, the moral case is one of engagement, diplomacy, influence and the long-term security and prosperity of British citizens.

Others believe that alliances cannot come at the expense of values. The Canadian prime minister Mark Carney recently warned that the world has entered an “age of rupture”, where the rules and norms that once governed international relations are beginning to fray. When Britain disagrees with its closest ally – particularly on questions of war and peace – it has a responsibility to defend those principles, even at the risk of friction or isolation.

So in these extraordinary times, should foreign policy be guided primarily by principle or by pragmatic self-interest? What should the balance be between ethical idealism and strategic reality? Can interests and values truly align? And ultimately, what is the role of morality in foreign policy?

Chair: Michael Buerk Panel: Matthew Taylor, Giles Fraser, Ash Sarkar and Tim Stanley Witnesses: Jan Halper-Hayes, Peter Oborne, Christopher Hill, Jamie Gaskarth Producer: Dan Tierney Assistant Producer: Jay Unger Editor: Chloe Walker.