Think Graham Greene and whisky, and the title that automatically pops to mind is The Power and the Glory. But The Human Factor, Greene’s 1978 tale of an interracial couple caught between the fronts in the Cold War, equals that work in both the quality of the writing and the obsession with booze.Greene’s favourite tipple was J&B, and he also made it the drink of choice for The Human Factor’s protagonist, Maurice Castle. Castle’s rationale, however, isn’t taste but appearance:He always bought J&B because of its colour — a large whisky and soda looked no stronger than a weak one from another brand. Like many of Greene’s protagonists, Castle is in the intelligence and espionage business, a world where private vices are not allowed.The same applies to private virtues, in Castle’s case, his love for his wife Sarah and stepson Sam, whom he as a British agent spirited away from apartheid South Africa.In a bizarre profession, writes Greene, anything which belongs to an everyday routine gains great value. Castle commutes daily from a modest London suburban home, always takes the same circuitous route home from the train station and relishes his after work drink:[Sarah] had carefully measured out a quadruple whisky by English pub standards, and now she brought it to him and closed the glass in his hand, as though it were a message no one else must read. Indeed, the degree of his drinking was known only to them: he usually drank nothing stronger than beer when he was with a colleague or even with a stranger in a bar. Any touch of alcoholism might always be regarded in his profession with suspicion. Only Davis had the indifference to knock the drinks back with a fine abandon, not caring who saw him, but then he had the audacity which comes from a sense of complete innocence. Castle had lost both audacity and innocence for ever in South Africa while he was waiting for the blow to fall.Like a number of a writers who served the cause of British intelligence, Greene worked for a spell for MI6 – under eventual defector Kim Philby.But Greene regarded it as “a silly, useless job” in a system of complete mutual distrust without winners and losers. Except for those whose lives were destroyed by it.The depth of that destruction is evident in a bit of pillow talk, in which Sarah asks Castle whether he would like to have a child of his own:“No,” he said.“Why not?”“You want to look under stones too much, Sarah. I love Sam because he’s yours. Because he’s not mine. Because I don’t have to see anything of myself there when I look at him. I see only something of you. I don’t want to go on and on for ever. I want the buck to stop here.”A fondness for J&B isn’t Maurice Castle’s only secret, as a series of mysterious phone calls to his house foreshadows at the beginning of the novel. Castle may want to disappear, but he’s not going to be allowed to.It’s ironic that Graham – by all accounts a bold connoisseur of drinking, adventure and other men’s wives – should have felt so drawn to meek anti-heroes who drown their anxieties about when the dime will finally drop.In his fiction, Greene developed a soft spot for the frailties and foibles that were the only human factors in the pitiless, mechanistic business of geopolitics. Whisky clearly warmed his heart.Graham Greene’s The Human Factor is available as a Vintage paperback