At 87, le Carré is publishing his 25th novel. He talks to John Banville about our ‘dismal statesmanship’ and what he learned from his time as a spy

I have always admired John le Carré. Not always without envy – so many bestsellers! – but in wonderment at the fact that the work of an artist of such high literary accomplishment should have achieved such wide appeal among readers. That le Carré, otherwise David Cornwell, has chosen to set his novels almost exclusively in the world of espionage has allowed certain critics to dismiss him as essentially unserious, a mere entertainer. But with at least two of his books, The Spy Who Came in from the Cold (1963) and A Perfect Spy (1986), he has written masterpieces that will endure.

Which other writer could have produced novels of such consistent quality over a career spanning almost 60 years, since Call for the Dead in 1961, to his latest, Agent Running in the Field, which he is about to publish at the age of 87. And while he has hinted that this is to be his final book, I am prepared to bet that he is not done yet. He is just as intellectually vigorous and as politically aware as he has been at any time throughout his long life.