The pen may be mightier than the sword, but Louis de Bernieres leans toward a gun. If he were Tony Blair, he would shoot himself if claims that Saddam Hussein had weapons of mass destruction prove unfounded, he has announced.

The novelist's denunciation is included in a collection of writers' views on the war in Iraq, which will make unpleasant reading for the prime minister.

Fifty of the 71 contributors were strongly opposed to the military action and a further 12 were undecided. Mr de Bernieres, whose best-selling Captain Corelli's Mandolin is set during the second world war, writes that in principle he favours forcible replacement of Stalinist and fascist regimes with democracies.

But he adds: "It is a shame that weapons of mass destruction were used as a pretext ... If they do turn out to be illusory, and I was Tony Blair, I would put a gun to my head and shoot myself out of sheer embarrassment."

Michael Holroyd, the biographer, observes that the prime minister "was as sincere as believers in the Flat Earth were sincere ... History will show him to have been a sincerely dangerous man."

Other opponents include Harold Pinter, and, perhaps more surprisingly, Jilly Cooper. Margaret Drabble, the novelist, warns that military action "suggests a dangerous trend of creeping American imperialism".

American writers are no kinder; Studs Terkel accuses Mr Blair of playing "Jeeves to a doltish Bertie W. [George Bush]".

The book's editors insist they were surprised at the strength of opposition to the war, despite drawing their inspiration from Nancy Cunard's 1937 collection Authors Take Sides, in which 127 of the 148 essays on the Spanish civil war supported the Republic side.

"She set out to arouse the indignation of her contributors; our collection was intended to present a truthful picture and stimulate [discussion]," said Jean Moorcroft Wilson, who worked on the project with her husband Cecil Woolf.

Mr Blair may draw solace from "reluctant hawks" such as journalist and novelist Ferdinand Mount, and John Keegan, the military historian, who is "strongly for" the war.

Opinions on the 1991 war, which will appear for the first time in the new book, Authors Take Sides on Iraq and the Gulf War, were far more evenly split.

Ms Moorcroft Wilson accepted that sceptics might question whether writers had greater insight into current affairs than other people, but added: "They are rational, inquiring, intellectually responsible - and rarely boring."