Julian Barnes has finally won Britain’s most prestigious literary award. This was the writer’s fourth time as a finalist for the Man Booker Prize. Up against what many critics considered a relatively thin group of competitors, Barnes, who once famously referred to the Booker as “posh bingo,” was widely expected to win the 50,000 British-pound prize (about $78,580) for his 11th novel, “The Sense of an Ending.”

Stella Rimington, former director-general of MI5 who writes spy thrillers, served as chairman of the 2011 judges panel and made the announcement in London on Tuesday night. “Julian Barnes’s ‘The Sense of an Ending’ has the markings of a classic of English literature,” she said. “It is exquisitely written, subtly plotted and reveals new depths with each reading.”

Rimington also defended the Booker finalists from louder-than-usual criticism. Detractors complained that the judges had dumbed down the prize to honor “readability” over literary quality. Indeed, the books on this year’s short­list have been the best-selling group in Booker’s history. Some critics responded with a rival contest called “The Literature Prize.”

“The Sense of an Ending” (Knopf, $23,95), released two weeks ago in the United States, describes a retired man anxiously reconsidering his responsibility for the suicide of a friend decades earlier. In a review in The Post, Jeff Turrentine wrote, “With his characteristic grace and skill, Barnes manages to turn this cat-and-mouse game into something genuinely suspenseful.”