The Irish author John Banville was the surprise winner of the Man Booker Prize tonight for his melancholy novel about a childhood reminiscence, beating the favourite Julian Barnes.

Banville, former literary editor of the Irish Times and Aer Lingus worker, won the £50,000 prize for The Sea, which tells the story of Max Morden, a boy whose life is changed by the arrival of a middle class family in his home village.

The story is narrated by an elderly Morden, now an alcoholic who is confronting a recent loss and trauma.

Banville was third favourite, behind Barnes and Kazuo Ishiguro, who had beaten him to the prize in 1989 with Remains of the Day.

He also saw off competition from some literary favourites, including Sebastian Barry, Zadie Smith and Ali Smith, to become the first Irishman to win the Booker since Roddy Doyle took the prize in 1993.

The chairman of the judges, Professor John Sutherland, described The Sea as "a masterly study of grief, memory and love recollected". He hailed the quality of Banville’s writing: "You feel you’re in the presence of a virtuoso. In his hands, language is an instrument."

But he acknowledged that the melancholic subject-matter made it a "slit your throat novel" which was perhaps too difficult for some readers - and some of the judges.

Professor Sutherland had to cast the deciding vote after the judges were split at the end of their one-hour judging session between Banville and Ishiguro.

"There were six novels that were all good - and then a bloody guillotine is coming down on your head in an hour. The discussion could have gone on for three days. There’s something abnormal about these novels competing. It’s very sad that you have to have a gladiatorial combat to get people to read good novels."

The Sea is Banville's 14th novel. His other works include an acclaimed 'scientific tetralogy', among them Dr Copernicus, the James Tait Black Memorial Prize winner and Kepler about the 6th-century German astronomer, which won The Guardian Fiction Prize. His was previously a Booker nominee for his 1989 novel, The Book of Evidence.

Born in Wexford, Banville had always wanted to be "an artist of some kind". He worked as a newspaper sub-editor for 15 years to make money. He has been writing novels since 1970.

The Booker judges included Lindsay Duguid, fiction editor of the Times Literary Supplement; the writer and antiquarian bookdealer Rick Gekoski; the novelist Josephine Hart; and David Sexton, the literary editor of the Evening Standard. The value of the Booker goes well beyond the £50,000 cash prize. Such is the impact on sales that publishers talk of 500 per cent uplifts on sales.

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