For all the crass and distasteful continuing attempts by some to compare Saddam with Hitler, the conflict that forms the centrepiece of Sir Christopher's memoir DC Confidential was, of course, the comparatively trifling invasion of Iraq. For three years, many have struggled with the consuming yet seemingly impenetrable question: why in the name of sanity did Britain have to get so involved?
Tens of millions of words have been spent on analysing the political and military issues that led to this uniquely baffling decision. And all the time, it boiled down to 15 words, as spoken to Sir Christopher in Downing Street on his appointment to Washington in 1997. "We want you to get up the arse of the White House," ran the briefing from Jonathan Powell, himself an erstwhile diplomat but then Tony Blair's chief of staff, "and stay there."
As a statement of foreign policy regarding dealings with the world's foremost power, it might be seen as short of detail and finesse. But what it lacks in elegance and completeness, it more than makes up for in clarity and pith. Those who've spent years rehashing the tired old gag about Mr Blair keeping a holiday home a few millimetres to the north of George Bush's colon may at least be gratified to learn that Mr Blair chose this property himself, and didn't delegate the deal to his wife or her crooked Aussie representatives.
In any other week, the serialisation of the book would be a dreadful humiliation to the Prime Minister, his entourage and those of his senior colleagues loftily dismissed in it as pygmies. Even with Wednesday's calamity in the Commons downgrading the coverage a little, it is quite embarrassing enough. No doubt Downing Street will move into smear mode when it catches its breath, but it won't be easy.
They can hardly dismiss Sir Christopher as ill-informed, since he was present at the crucial meetings between Bush and Blair. They can't dismiss him as a peacenik, since he is one of the elite corps who claims still to agree with the war. They might try to portray him as a covert socialist, motivated by rancorous ideological hatred of New Labour, on the strength of his bright red socks. But given the warmth with which he writes of Mrs Thatcher, and his time at Peterhouse under the tutelage of the recently deceased Maurice Cowling, that high camp granddaddy of Thatcherism, this won't wash. They cannot even accuse him of greed, since the current boss of the Press Complaints Commission has given the £250,000 paid in serialisation rights to children's charities.
If the best they can do is charge him with disloyalty and breach of confidence, yet an administration with such a record of briefing against its own, in which Alastair Campbell was permitted to keep a daily diary ("my pension"), is hardly on strong ground there. At worst, it is a betrayal of etiquette, but one most will happily forgive in the grander scheme of things.
No, with Sir Christopher they are absolutely stuffed. In his wry and literate way, Meyer fleshes out the bones of what's been a pretty familiar skeleton ... a star struck giant ham of a PM with infinitely more interest in feeding his gargantuan ego than anything else, great at florid rhetoric but without the discipline to master detail, surrounded by some of the most spineless and spiteful apparatchiks, elected and unelected, that even British politics has yet produced.
He shows us John Prescott attempting to engage a Senator in debate about the situation in Kovosa, and the Balklands in general, as poorly briefed as he was aphasic. Geoff Hoon quivers with nerves in the presence of Donald Rumsfeld; and also tongue- tied and intimidated when dealing with the Americans, and slow to master a brief, was that über-nebbish Jack Straw.
Amusingly out of their league as these bit-part players appear, it is, of course, Mr Blair who commands centre stage, and the most revealing vignettes are also the most banal. Here we see the power of the shopping-list theory of history - the notion that the greatest insight sometimes comes from the most trivial minutiae. The case of the wrong trousers comes to mind. Sir Christopher relates how, one weekend at Camp David, Mr Blair "put on a pair of ball-crushingly tight, dark-blue corduroys. I was later told that his wardrobe for the weekend had been the result of intensive debate within No 10. If true, it was not wholly successful. Bush looked pretty relaxed. By contrast, Blair looked uncomfortable, his efforts to appear similarly insouciant undermined by the inability to get his hands fully into pockets that appeared glued to the groin."
The thought that, as the war for the future of Western democracy approached, the PM and his advisers were obsessing about his cords says enough about the priority imbalance between substance and style. As for the symbolism of Mr Blair being prepared to sacrifice his testicles in the cause of ingratiating himself with the President, that too speaks for itself. So does the image of Mr Blair rushing out of dinner just as Bush was about to toast his dear friend and ally, and back to his guesthouse to change when he realised he was the only one present wearing jeans. Not smart, not casual, and no reverse gear indeed.
Strongly suspecting that Mr Blair was always that poodle of cliché is one thing. Knowing that he actively determined to insert himself in the presidential rectum (and that he sought to circumvent the embassy when he felt that it wasn't far up enough) is quite another, and for this confirmation we owe Sir Christopher much thanks.
His talent for comic observation and understated wit is a great bonus, albeit, as I say, he has some way to go to match Sir Archibald Clark Kerr. "My dear Reggie," he wrote to his friend Lord Pembroke, the foreign office minister, when the war without compare was at its gloomiest. "In these dark days, man tends to look for little shafts of light that spill from Heaven... So I propose to share with you a tiny flash that has illuminated my sombre life, and tell you that God has given me a new Turkish colleague whose card tells me that he is called Mustapha Kunt. We all feel like that, Reggie, now and then, especially when spring is upon us," concluded this trail blazer for diplomatic comedy, "but few of us would care to put it on our cards."