John le Carré's son Nicholas has confirmed that his father became an Irish citizen before his death in December 2020 as a result of his Brexit disillusionment.

A BBC documentary which is set to be broadcast on Saturday will see Nicholas discuss John le Carré's decision to embrace his Irish heritage, in a twist worthy of his great thrillers.

Under his real name of David Cornwell, le Carré served as a British diplomat and as a spy for the counter-intelligence agency MI5. The novels that garnered him immense fame, after his third thriller, The Spy Who Came in from the Cold in 1963, form a penetrating anatomy of Britain’s decline as a world power.

George Smiley, hero of the trilogy of novels, Tinker Tailor Soldier Spy (1974), The Honourable Schoolboy (1977) and Smiley’s People (1979), is one of the archetypal English characters ever created. Many critics feel that Smiley's anguish over choosing loyalty to his country over his moral compass epitomising Britain's larger societal dilemmas as a colonial, imperial power.

But in the BBC Radio 4 documentary, A Writer and His Country, le Carré’s friend and neighbour - writer and human rights lawyer Philippe Sands - dives into le Carré's increasing unhappiness with England after the Iraq war of 2003. He was known for deeply opposing Brexit, and the election result cemented the writer's sense of alienation as he was determined to remain a European citizen.

At the time of his death, le Carré’s friend, the novelist John Banville, confirmed that the English writer had researched his family roots in Inchinattin. Located near Rosscarbery, Co Cork; le Carré was entitled to apply for an Irish passport through his maternal grandmother, Olive Wolfe.

It was not known until now that he had completed the process of becoming an Irish citizen. His son Nicholas says that “the Irish connection was very real and it mattered to him very much”.

The archivist who was helping le Carré to research his roots in Skibbereen reportedly bid him welcome home, which "was vastly moving for him, a huge emotional shift, an awareness of history and self which had genuinely eluded him his whole life”.

Nicholas Cornwell recalls that, “On his last birthday, I gave him an Irish flag, and so one of the last photographs I have of him is him sitting wrapped in an Irish flag, grinning his head off. He died an Irishman.”

A Writer and His Country will be broadcast on BBC Radio 4 on Saturday evening.

Other well-known faces with Irish passports include Sex Pistols singer Johnny Rotten, Martin Sheen, Olivia Wilde, Mel Gibson, Mischa Barton, Gene Kelly, and comedian Katherine Ryan.