Victor Rothschild was not a Soviet spy. The evidence against him was of the sort the security services specialise in: vague, circumstantial and based on gossip and innuendo. He argued in 1944 that British and American military secrets ought to be given to the Russians. He fixed up the deal between the retired spy Peter Wright and the journalist Chapman Pincher that resulted in Pincher's Their Trade Is Treachery and Wright's Spycatcher; he knew Guy Burgess and Anthony Blunt rather more closely than he liked to admit in later years; Rupert Allason, the former Conservative MP who is otherwise known as the spy writer Nigel West, claimed (wrongly) that he was a Communist Party member at Cambridge in the 1930s.
Yet I find it impossible to share his friend and biographer Kenneth Rose's furious indignation at the way the rumours clouded Rothschild's last years. In Rose's demonology, Allason and Wright are closely followed by Wright's Australian lawyer Malcolm Turnbull, who made the British establishment look so inept and untrustworthy when the Thatcher government tried to persuade the Australian courts to ban Spycatcher.
Rose paints an affecting picture of Turnbull persuading Wright to expose Rothschild's role in the book's publication - to "betray" Rothschild, as he puts it - with Wright saying at last: "Oh, well, poor dear Victor. Throw him to the wolves." Turnbull is even deprived of what some thought was his major contribution to the English language. It was under his relentless cross-examination that the British cabinet secretary, Sir Robert Armstrong, said he had not lied but had been "economical with the truth". The distinction, Rose points out indignantly, goes back to Edmund Burke.
The truth is that Rothschild was as much a part of the grubby, reactionary, self-glorifying world of the security services as Allason, Wright or Pincher. There are no blacks and whites in that world, only dirty, duplicitous greys. In the twilight of his life, says John le Carre, the good double agent can turn to his masters and say: "I have served you both well." When faced with the potential revelation of half-truths, their instinct is not to reveal the whole truth, but to manoeuvre - as Rothschild did with Wright and Pincher - to try to ensure that it is their half-truth that gets told. The distinction between spies and agents provocateurs is a fine one.
However, you do not have to share Rose's conclusions in order to recognise that this is a fine biography. The heir to the huge fortune of the British branch of the Rothschilds, Victor Rothschild was fabulously rich all his life without the inconvenience of having to earn money. He was a scientist of some distinction before the Second World War, and a valued MI5 officer during it (and close to it all his life). From 1958 to 1970 he was a senior executive with Shell. In 1970, the new prime minister Edward Heath made him the head of the Central Policy Review Staff, a government think-tank eventually abolished by Margaret Thatcher. In 1975, at the age of 64, he finally consented to join the family firm of N M Rothschild and Sons, in the role of chairman.
Rose never lets his affection for his subject prevent him from showing how repellent he could be. After his divorce from his first wife, Rothschild was apparently "hurt when those he supposed to be his friends went to see Barbara at her new home". More than 40 years later, he found it upsetting to read of her happiness. His second wife found him hard work: "It did not take much in the home to evoke a frown or a rebuke delivered in a menacing drawl: an unwelcome experiment in the kitchen, perhaps . . . " Her responsibilities, Rose reports dryly, "went far beyond those of other wives". Rothschild once told Rose that the doctor had put him on a strict diet to lose weight, and Rose pointed out that, in that case, "you should not be drinking that sweet vermouth"."Yes," replied Rothschild, "I wish Tess would get me off it."
Rose has an eye for a good story, however irrelevant. I am grateful to him for the revelation of how Sir Alec Douglas-Home, as foreign secretary, reduced the burden of his paperwork. One day, a private secretary placed in his box a two-inch-thick report on Icelandic fisheries, with a note: "The Secretary of State may care to read this during the weekend." Sir Alec minuted: "A kindly thought, but erroneous."