John le Carré’s latest novel returns the reader to the years of the Cold War and to the betrayals and duplicity of the secret world. We are reintroduced, in A Legacy of Spies (reviewed on page 42 by William Boyd), to some of his most enduring characters, including the spy­master George Smiley, pictured above played by Alec Guinness, and Peter Guillam. The book is a prequel as well as a coda to the 1963 novel The Spy Who Came in from the Cold, the international success of which liberated David Cornwell (le Carré was a pseudonym used to protect his diplomatic cover) fully to pursue the writing life.

In the penultimate chapter of A Legacy, Guillam visits his former colleague Smiley, who is now elderly and living in Freiburg. They reflect on the old days, on what they got right and wrong, as well as the inevitable moral compromises of the spying game. At one point, Guillam asks whether it had been worth the struggle and sacrifice. He wonders what it was all for. Was it for England? Smiley ponders and then replies:

There was a time, of course there was. But whose England [le Carré’s italics]? Which England? England all alone, a citizen of nowhere? I’m a European, Peter. If I had a mission – if I was ever aware of one beyond our business with the enemy, it was to Europe. If I was heartless, I was heartless for Europe. If I had an unattainable ideal, it was of leading Europe out of her darkness towards a new age of reason. I have it still.

Smiley – whose allusion to Theresa May’s 2016 Conservative party conference speech will be noted by the alert reader – is not alone in yearning for a new age of reason. But these are unreasonable times, as the Brexit debacle demonstrates. Darkness is falling wherever one looks: the US, the Korean Peninsula, Vladimir Putin’s Russia, the former eastern bloc states of Poland and Hungary, Myanmar, the Middle East.

In Britain, we are suffering from a catastrophic loss of confidence in our national leaders. How else to account for the fact that Jacob Rees-Mogg, a pantomime toff with unpleasant hard-right convictions, is the choice of Conservative Party members to be their next leader, and thus our prime minister? Worse still, the United Kingdom seems to have no coherent foreign policy. The Conservative Party is introspective, split between Remainers and Brexiteers. The Foreign Secretary, Boris Johnson, is received with ill-concealed derision in most foreign capitals. Foreign Office mandarins consider him to be lazy and unserious. The most significant speech on international affairs this year was given not by Mr Johnson but by Theresa May in Philadelphia in January, when she renounced Blairite (or neoconservative) interventionism and attempted to outline a new “realist” foreign policy.

But since her humiliation in the general election, Mrs May is much reduced. Her distinctive brand of communitarian conservatism (which was never properly articulated in the election campaign) has been replaced by a pragmatic survival strategy. And the Prime Minister has been captured by the Brexiteers, who wish to keep her in office until she can no longer deliver what they want.

Meanwhile, what is strikingly absent from the Brexit debate is any larger sense of Britain’s role in the world. Brexit is a retreat from responsibility. The rhetoric about a liberated, buccaneering “global Britain” is so much cant, the delusions of empire nostalgists or Randian free market ideologues.

Yet what has Labour got to say? As we listened to Keir Starmer on The Andrew Marr Show on 3 September tortuously attempt to explain his party’s revised position on Brexit, we were struck by the intellectual impoverishment. In truth, Labour has next to nothing to say about Britain’s role in the world. It has had nothing substantive to say about the nuclear stand-off in the Pacific, which threatens the balance of power in south-east Asia. While Mr Starmer goes on about the single market and extended “transition” periods, the UK is losing influence.

Inside the European Union and as the so-called Atlantic bridge to the US, the UK could shape the destiny of Europe. Outside the EU and considered increasingly marginal by world leaders, Brexit Britain, in its less than splendid isolation, will be in no position to lead Europe towards George Smiley’s longed-for “new age of reason”.