British spy author John le Carre's Brexit animosity drove him to become an Irish citizen shortly before he died last year, his son revealed on Thursday.
"He was, by the time he died, an Irish citizen," Nick Cornwell told the BBC.
"One of the last photographs I have is of him sitting wrapped in an Irish flag, grinning his head off."
Mr Cornwell said his father visited his grandmother's native city of Cork in Ireland and experienced an "emotional shift".
EU member Ireland allows individuals with Irish parents or grandparents to claim citizenship, and there has been a boom in applications since Britain's 2016 referendum decision to split from the EU.
The former British intelligence officer, whose real name was David Cornwall, wrote 25 novels and one memoir, and sold 60 million books worldwide in a career spanning six decades.
His intricate espionage novels are celebrated for weaving morally shady worlds inhabited by compromised characters and corrupting institutions.
His writing chronicled post-empire Britain from the Cold War until the present day and did not shy from scathing criticism.
An avowed Europhile, he was an outspoken critic of Brexit and at the general election in 2019 said Britons should "join the resistance" against UK Prime Minister Boris Johnson.
"My England would be the one that recognises its place in the EU," he said in 2017.
"The jingoistic England that is trying to march us out of the EU – that is an England I don't want to know."