David Manning finds trouble wherever he goes. A week into his present job - special foreign policy adviser to the Prime Minister - he went to Washington to introduce himself to the US administration. He decided to fit in a couple of meetings in New York before returning to London. From his window seat of the shuttle as he flew over Staten Island, he saw smoke coming from the first tower of the World Trade Center. He had no idea what was going on.
When the plane landed at JFK, the passengers were herded into a lounge. There, on a giant television screen, he saw the second tower go down. They were ordered out of the terminal building. After collecting his luggage, Manning waited for two hours for a cab, although with mobile phones out of action he didn't know where he should go. He met a young British couple in the queue and they decided to find a hotel. They ended up in Queens. Manning asked the receptionist for two rooms for the night. The man was astonished: this was a place where you hired rooms by the hour.
The next day, Manning managed to make contact with the embassy in Washington. They sent a car for him and he was back in business.
His business is running Britain's foreign policy. Unbeknown to the public, Sir David Manning has become one of the most important people in the country. Since 11 September, it is to him that Tony Blair turns first for advice. It is Manning who is running the conflict with Iraq. It is he who is guiding relations with the Bush-led White House, he who deals with the Israelis, the various Arab governments, the Russians, the Chinese.
He doesn't just do Blair's bidding in diplomatic channels and in Whitehall. A diminutive, super-bright owl of a man, Manning, 51, does not just reflect policy. He is instrumental in setting it. "When David Manning opens his mouth," says one diplomat who has seen him close up, "we know it's the Prime Minister speaking."
Manning comes across as an old-fashioned civil servant. There is nothing flashy about him. He is assiduous, polite but not oleaginous, and extremely modest. But these traits provide cover for a mind that works at ferocious speed. He was schooled in traditional Nato thinking - that America is the pivot for the "free world", that it must be constantly prodded to stay engaged, and that in times of trouble, diplomacy must be reinforced by the threat of force.
Blair concluded at the end of his first term that he needed a stronger and bigger foreign policy set-up in Downing Street. He created two full-time advisers with their own teams. Sir Stephen Wall was brought in to run European Union affairs, while Manning would do the rest. The changes were unprecedented and reinforced accusations of presidentialism. With 9/11, Manning's job went from being important to pivotal. From his spartan office on the ground floor of Downing Street, he has micromanaged the crisis. His relationship with Condoleezza Rice, Bush's national security adviser, has been particularly crucial. The two didn't know each other before, but they shared a common interest in Kremlinology. "David" and "Condi", as they call each other, talk at least once a day, often more so.
The very public battles between Colin Powell's more UN- oriented approach and the Dick Cheney-Donald Rumsfeld "give 'em hell" camp provided Blair and Manning with an opportunity. Rice is the conduit to Bush and it is largely through her that Blair wields whatever influence he does. This is where Manning counts. "There's a lot riding on that relationship," says a Downing Street official. "They've held things together when they could easily have fallen apart."
In Washington, the idea that a figure as significant as Manning, even as a career civil servant, could conceivably be protected from scrutiny would be inconceivable. Rice, for her part, has to account for herself to Congress and on television. "Only the Brits could keep someone as important as Manning out of the public eye," says one US official.
British civil servants, according to the old adage, have to be content with what their political masters propose. Manning's view of the world is close to the one Blair has come to take. He has consistently urged the Americans to give the UN one last chance to get the weapons inspectors back into Iraq. But he is equally convinced that even if they go in, which Saddam Hussein has now agreed to, military action should follow quickly if Iraq does not fully comply.
Manning has argued strongly that influence with the US comes only through keeping alongside the Americans and playing down differences wherever possible. Even so, speeches from members of the Bush administration are sometimes met with grimaces in Downing Street. When Rumsfeld gave a speech to Pentagon staff last month and spoke of the "so-called occupied territories" (he was referring to the West Bank and Gaza), he reinforced fears in No 10 and the Foreign Office that, as one official puts it, they "were back on a headbangers' agenda".
This highlights one area where Manning has conspicuously not brought his influence to bear. The British have tried, gently, to persuade the Americans to revive the Israeli-Palestinian peace process at the same time as preparing for war with Saddam, but they have been ignored.
Manning goes along with the new Labour patina, the attempt to put a moral gloss on the pragmatism that has always governed Britain's conduct abroad. But he is a strategist rather than an idealist. He stresses the importance of not just having good intelligence information, but knowing how to use it. He regularly attends the cabinet's Joint Intelligence Committee (JIC), which co-ordinates Britain's spooks and which is now putting together the "dossier" on Saddam.
His career is pure establishment. Public school at Ardingly was followed by modern history at Oriel College, Oxford. He met his wife, Catherine, at a lecture in their freshers' term. His contemporaries recall him as studious. This was the heady days of student revolt in the late Sixties, but he didn't get involved.
After early postings in Warsaw, New Delhi and Paris, Manning's first senior position was in Moscow. The locations have provided a useful backdrop for Catherine. Her thrillers, written under the nom de plume Elizabeth Ironside, revolve around murders of British diplomats in far-flung places and Russian mafia bosses infiltrating the murky global art world.
Manning was in Vilnius in January 1991 when troops opened fire on demonstrators. On the first day of the coup against Mikhail Gorbachev, he happened to be in charge of the embassy. He was the one who sent the telegrams back to John Major's government. Four months later, on Christmas Day, he sent the note back to London announcing that the Soviet hammer and sickle was being lowered from the Kremlin and replaced by the tricolour of the new Russian republic. "I am watching the red flag coming down," he wrote.
He may have had a journalist's knack for capturing the moment, but Manning has never lapsed into fashionable thinking. He subscribed to Robert Conquest's unromantic notions of Soviet power. He scoffed at Francis Fukuyama's notion of the end of history, seeing in the collapse of the USSR a moral good but also a geo-strategic danger. Drawing President Putin into the western fold has been high on his list of priorities. Intriguingly, several of Manning's colleagues in Moscow have also become key players behind the scenes in the government. John Scarlett is now chairman of the JIC, while Francis Richards runs the GCHQ listening centre in Cheltenham.
On his return from Moscow in 1993, Manning briefly headed the Foreign Office's eastern department at the height of the conflict in the former Yugoslavia. He then became prominent in the five-nation "contact group" on Bosnia. During the later Kosovo war, Manning was convinced of the ethical case for military intervention - with or without a UN resolution. "He was outraged by what the Serbs were doing. He never had any problems with that war," says a colleague.
In November 1995, he was given his first ambassadorial post - to Israel. As he was packing his bags, Yitzhak Rabin was assassinated and the course of Middle Eastern history changed. A few months later, Likud's Binyamin Netanyahu had taken over, heralding a far more aggressive Israeli approach. Manning had been appointed precisely because he didn't fit the Israelis' stereotype of the "Arabist" British diplomat. But his relations with Netanyahu and the foreign minister, David Levy, were frosty. When, in March 1998, Robin Cook was heckled and jostled as he visited Har Homa, a housing estate that Israelis had begun to build on the outskirts of Jerusalem on land the Palestinians consider theirs, Manning was by his side.
After three years in Israel, Manning returned to London as deputy undersecretary, the number two mandarin at the Foreign Office. From there he was sent to head Britain's delegation to Nato in Brussels, only to be recalled personally by Blair.
The question Whitehall watchers are now asking is whether Manning will be despatched as ambassador to Washington next February when the incumbent, Sir Christopher Meyer, returns to London to take over at the Press Complaints Commission. If he wants it, the job will surely be his, but would he at this pivotal moment want to give up being Blair's window on the world?