Were he alive today, though, it is clear that his avowed anti-Americanism would have made him a keen opponent of the US involvement in Iraq (news - web sites), just as he was highly critical of the Vietnam war and, later, of president Ronald Reagan (news - web sites)'s foreign policy.

Not only did he characterise the dangers of American imperialism, as he saw it, in Vietnam in his novel "The Quiet American", but he was openly scathing of the war, telling V.S. Naipaul in a 1967 interview, recently resurrected and republished to mark the centenary of his birth: "The Vietnam war is not only horrible but foolish ... There is something menacing about great power combined with great foolishness."

In truth, Greene was nothing if not political, both in his life, rubbing shoulders with world leaders like Fidel Castro (news - web sites) and Mikhail Gorbachev, and in his writings, in which he seemed to be conducting a constant personal dialogue between the committed Communist he had been as a young man and the Catholic convert he became in order to marry his wife, Vivien.

All his best work, "The Heart of the Matter", "The Power and the Glory", "A Burnt-Out Case", "Brighton Rock" and "The End of the Affair", for example, are marked by a struggle between the secular and the spiritual.

Nowhere was this better illustrated than in his late work "Monsignor Quixote", on the face of it a quaint re-telling of Cervantes' Spanish classic "Don Quixote" with a self-effacing cleric and a Communist politician as the two heroes, but in reality an ultimately unresolved discourse on the relative merits of religion and politics.

An inveterate traveller all his life, Greene followed his celebrated news sense and went to troublespots around the globe, from Africa to Asia and Latin America.

For a man who wrote "England Made Me", he found his native land too narrow to hold him and spent the last 25 years of his life in exile in France, and all but a couple of his post-War novels were set outside Britain.

Greene's novels were also characterised by betrayal and treachery, stemming partly from an unhappy childhood but also from his links with British Intelligence, including his close friendship with the Soviet spy Kim Philby, who ironically came to be known as "the third man", after the title of Greene's best-known work, the film of the same title set in post-War Vienna with Orson Welles as the treacherous Harry Lime.

But for all his reticence, Greene was far from a bore or a killjoy: his private life was a mess (he described himself as "a bad husband and a fickle lover") and his indulgence in alcohol legendary.

His infidelities were legion, although he never divorced his estranged wife, and he had affairs by the dozen, including the celebrated dalliance with the beautiful American wife of a British aristocrat with whom he cavorted across Europe and even for a time set up home with in Capri. She was said to be the inspiration for the woman at the heart of "The End of the Affair", arguably his most "Catholic" novel.

Always a heavy drinker, Greene was renowned for his capacity, as fellow-novelist Anthony Burgess once remarked admiringly: "The human liver can only stand so much, unless it belongs to Graham Greene."

And stories were told by visitors to his home in Antibes in the south of France, in the years before his death in April 1991 at the age of 86, of how Greene would have a half-pint glass of neat vodka set before him and announce mischievously: "My doctor tells me I am only allowed one drink a day. This is it."

But ultimately, Greene was a man who invested great energy in staving off his greatest enemy, boredom, which even famously once led him to experiment with a game of Russian roulette with a live bullet in the gun.

His work is still politically relevant to the modern world and has lost none of its cutting edge, although Greene is no longer read as much as he was in his lifetime.

But the sense of living on a frontier "on the dangerous edge of things", as he himself put it, and the curious atmospheric settings, dubbed "Greeneland", an ill-defined netherworld where loneliness and despair are never far away, mean that the novels more than repay the time they take to read.