Catherine was the dedicatee of Greene's novel The End of the Affair; their own affair began with a painful confrontation with her husband, a rich farmer who later became a Labour peer; before the affair had reached its end, the guilty couple had 'committed adultery behind every high altar in Italy'. It's all good stuff. It feeds our insatiable appetite for salacious gossip about the famous - and it all calls into question Greene's career and reputation. By the end of his life he was widely described as our greatest living writer. Some of us not only doubted that, but quietly wondered whether he was ever entirely serious or sincere about anything?
There is an element of treachery in my saying this. Fifteen years ago I used to meet Greene (at the Spectator, where I was literary editor, a job he had held about 40 years earlier). I liked him, was innocently proud to know him, prouder to have lunch with him, proudest of all to receive friendly letters with that curious stylised signature in which 'GG' looked rather like the zigzag emblem of the S S. Still, treachery was one of Greene's own favourite themes, from his doting enthusiasm for Philby, Burgess and co, to his elaborate exploration of adultery, in fiction and in real life.
Adultery and treason are both serious subjects, or can be. But they appealed to Greene because of the scope they offered for games-playing. When someone once asked Anthony Blunt why he had done it, he murmured: 'Cowboys and indians, cowboys and indians.' Greene would have understood. Life, love, literature - all were for him a form of game. He loved to tease and he loved practical jokes: both symptoms of unhappiness, and of the pathological restlessness of a man who finds seriousness unbearable.
He was playing games as a boy when he experimented with Russian roulette; he was playing a different sort of game towards the end of his life when he said, 'I would rather end my days in the Gulag than in California' (words that are not so much silly or odious as incapable of being uttered seriously). He was playing games when he 'spied' for the secret service. He was playing games behind the altar with Mrs Walston - and in front of the altar before that.
Greene was famously a Catholic convert, and a 'Catholic writer'. He claimed to resent the label, but that was fair cheek coming from someone who had written books like Brighton Rock, The Power and the Glory, or The Heart of the Matter. The truth was that his conversion to Catholicism was a smart career move, even if he didn't realise it at the time. George Orwell pointed out that one reason many good novels were being written by Catholics was because 'the conflict not only between this world and the next world but between sanctity and goodness is a fruitful theme of which the ordinary, unbelieving writer cannot make use'.
But Orwell also saw what was wrong with, and indeed false about, The Heart of the Matter. Quite apart from the absurdity of its plot and of Scobie's elaborate suicide - 'White all through, with a stiff upper lip, he had gone to what he believed to be certain damnation out of pure gentlemanliness' - the book reeks of bad faith. Or perhaps of pretended faith. By the end of his life, Greene liked to describe himself as a 'Catholic agnostic', whatever that might be. But almost from the beginning there was a flavour of insincerity and of affectation. As Orwell saw, The Heart of the Matter is not only an essentially frivolous book, it represented 'a weakening of belief, for when people really believed in Hell they were not so fond of striking graceful attitudes on its brink'.
Another contemporary likewise saw through the book. Evelyn Waugh was gentler than Orwell - he was a devoted if sometimes despairing friend of Greene's - but he, too, disliked that same attitudinising. Scobie's self-damnation for the love of God was 'either a very loose poetical expression or a mad blasphemy'.
In the end there is a stark comparison between those two friends, fellow-novelists and ostensible co-religionists, which even those who find Waugh's personality and beliefs unsympathetic should see. Noel Annan - no religious or political reactionary - has acutely said that Waugh is not only a better writer than Greene but has a view of life and its purposes which, whether one shares it or not, is far more logical and coherent. Waugh was tormented, like Greene, but in a different way: tormented by the complete sincerity of his faith, not least his belief in the reality of the 'four last things': death and judgment, Heaven and Hell. If Greene was tormented it was by his own insincerity. That is why I am convinced that Greene's reputation will not only undergo the usual eclipse that follows a writer's death but will stay in eclipse.
There are already signs of this. Ten or twenty years ago it was dangerous to query Greene's status as the greatest living writer, or to point out that his latter books - Doctor Fischer of Geneva an egregious example - were such tripe that they would not have been published under any other name. Now, more writers, critics and readers publicly wonder how some of his books could ever have been taken seriously. To be fair to that amiable old farceur, there is no very strong evidence that he himself took them much more seriously than he did his babyish political opinions, or his capering behind altars with someone else's wife.