There are several reasons for this reluctance to engage with the lives of people who have not yet featured in the obituary columns.
One is the sheer weight of incidental baggage: the dissentient voices of close friends who imagine themselves traduced or overlooked; the ‘sensitive’ material that may not yet be available for use.
But another is the lurking presence of the biographee, who even if he or she collaborates, has a fatal habit of falling out with the writer, peddling well-nigh mythical versions of the achievements (or failings) on display and calling the whole reliability of the project seriously into question.
While there is no hint in this mammoth endeavour’s lengthy introduction that Sisman fell out with John le Carré, or “David” as he rather breezily calls him, there are a great many hints that not all of this four-year voyage to the heart of the modern espionage novel was plain sailing.
“It would be disingenuous to suggest that there have not been difficulties,” the biographer writes at one point, before going on to lament le Carré’s diffidence in the matter of “his time serving in the intelligence services”.
We hear talk of multiple, variant versions of key events, while in a recent BBC Radio Four interview, Sisman complained that he had been “gazumped” by the news that his subject was now at work on a memoir.
A sly old fox? An arch-manipulator? A top-notch raconteur who sometimes allows style to prevail over substance? Each of these descriptions of the author of Tinker, Tailor, Soldier, Spy (real name David Cornwell) and the creator of George Smiley, has something to be said for it.
What cannot be denied, on the other hand, is the extraordinary fascination of le Carré’s early life, even if the starring role in it happens to be played by someone else. This is the gargantuan figure of Ronnie Cornwell, le Carré’s father, a swindling confidence trickster and emotional havoc-wreaker of such unalloyed chutzpah that he could have stepped straight out of a novel by Charles Dickens or H.G. Wells, and whose career would probably require a stack of Inland Revenue files to do it justice.
Still, Sisman does his best with this beguiling fantasist, whose courtiers were apparently so fascinated by him that they were prepared to go to prison on his behalf.
He is, for example, attentive to the bankruptcy of 1935, when Ronnie’s outgoings exceeded his incomings by a factor of almost 20-to-one, and offers a forensic analysis of an early 1950s meltdown when a commercial empire that involved directorships of 60 limited companies and declared interests in another 39, collapsed beneath a tax demand of £61,889.
Ronnie’s assets at this point amounted to a princely £129.12s. Thirty years later there is an even more bracing moment when le Carré’s half-sister Charlotte, then appearing in a film about the Krays, is shown the family photo album by Ron and Reggie’s elder brother Charlie.
What favours did Ronnie extend to be pictured with an arm flung round each of the Kray twins? We shall never know.
Quite as unsettling as a lifetime’s chicanery, though, was the mixture of emotional blackmail and constant jockeying for position that Cornwell pere brought to the father-son relationship. A mostly-absent parent, capable of disappearing to far-flung corners of the world for months at a time, Ronnie had an unnerving habit of popping up when David least expected or wanted him to and attempting to collar the limelight for himself.
Appearing unexpectedly at the American launch of one of le Carré’s novels, he could be heard referring to “our book”. Visiting Chicago not long afterwards, le Carré was told by the Foreign Office that his father had been arrested in Indonesia for suspected gun-running. Bailouts rarely did the trick, as the old man rightly suspected that he was paid for his silence.
All this naturally worked its effect. Preternaturally self-reliant, cautious and industrious, le Carré, born 1931, found the hurdles of boarding school – to which he was first sent at the age of five – easier to negotiate than more cossetted contemporaries.
His first real enthusiasm was art, swiftly followed by the German language, which sent him on a pre-university study trip to Bern. Even during his National Service days in Europe there were forays into the world of Cold War-era intelligence. Waved on by his talent-spotting Oxford tutor Vivian Green, who clearly contributed something to Smiley, le Carré’s eventual arrival at MI5, after a period spent teaching, looks almost pre-determined, a human iron filing dutifully obeying the magnet’s call.
Not that the late 1950s “paper world” of the Secret Services was a particularly attractive place. “For a while you wondered whether the fools were really pretending to be fools, as some kind of deception, but alas the reality was the mediocrity,” he later wrote.
A transfer to MI6 saw him attached to the British embassy in Bonn (the setting for A Small Town in Germany, 1968), where pre-war standards of snobbishness were vigorously maintained. Congratulating the housekeeper once on her cooking, le Carré collected the rebuke "Can't you act like a gentleman and not talk to the servants?".
Senior officers who later took issue with his novels (“John le Carré hasn’t done us any good. He makes all intelligence figures look like philanderers and drunks”, one of these remarked) noted the presence of an anti-Establishment rebel tilting at “the old school tie”.
On the other hand, here, unquestionably, was the by-now aspiring novelist's subject matter. A first novel, Call for the Dead, had appeared as early as 1961, but it was The Spy Who Came in from the Cold, two years later, that propelled him into the big time.
As Sisman notes, the money shower then descended on his head and the company of the famous seriously upset his personal equilibrium. An affair with Susan Kennaway, the wife of his fellow novelist James, led to the collapse of his first marriage and the advent of what Sisman calls “a compulsive search for love”. His second wife, Jane Eustace, who previously worked for his British publisher Hodder & Stoughton, is apparently more tolerant of his infidelities.
The mention of money showers, searches for love and marrying the woman who used to sell your foreign rights, hints at another of Sisman’s procedural difficulties. If writing a biography of a living subject has its problems, then these drawbacks are infinitely worse if he or she happens to be a successful writer.
For what do successful writers do, it might be wondered, except write their books and enjoy, or cope with, their success? It is almost inevitable, consequently, that the second half of John le Carré: The Biography should turn out to be a bit less entertaining than the first.
Not only is Ronnie dead (“He’s taken everything I’ve got,” his third wife remarked) by now, but a pattern has set in.
A novel gets written, sold, reviewed and filmed. A quiet period of reflection and foreign travel ensues, followed by the repeat of the process a year or so later.
Le Carré, meanwhile, emerges as a rather single-minded character, commercially astute, never averse to sacking hirelings who have let him down and horribly sensitive when it comes to criticism of his work.
Sisman is possibly a shade too polite to probe the vexed question of his subject’s literary reputation with the rigour it deserves. He does, however, quote the opinion of Clive James who, noting that le Carré’s work can be divided into “entertainments” and serious stuff, claimed to detect “strong evidence that le Carré is out to publish a more respectable breed of novel than those that fell into the first category”.
Did these succeed? James thinks that “it was the merely entertaining books which had the more intense life”. In the end, you suspect we shall come to regard le Carré’s deglamorisation of espionage as his real achievement.
The distinguishing mark of novels such as The Russia House (1989) and A Most Wanted Man (2008), after all, is their matter-of-factness, the sense that all those involved are merely getting on with their work.
However much we might not want to admit it, spying – like authorship - turns out to be just as much a job as any other activity.
DJ Taylor is a novelist and critic whose journalism also appears in The Independent on Sunday and The Guardian.