When Barack Obama arrived at No 10 yesterday, he looked happy, relaxed and pleased to be there. He smiled and waved to photographers on the other side of Downing Street, calling a cheery, "Hello!" Camera flashes caught Gordon Brown waiting for him in the shadows of the hallway.
But when the US presidential candidate came out again two hours later, after a long chat with the beleaguered Prime Minister, he looked shattered. The smile had faded. Now he spoke so softly that only the closest microphones could hear him. As usual, the cut of his sharp, dark suit echoed the Kennedy era, but the charisma had drained away.
He had no advice for Mr Brown. But he did have an observation. "You're always more popular before you're actually in charge of things," he said. "Once you're responsible, you're going to make some people unhappy."
Hundreds of yards away, invisible behind iron gates and security barriers, supporters chanted "Obama! Obama!" and there were cheers. Those haven't been heard in Downing Street for a while.
Mr Brown stayed indoors, as protocol demanded. He couldn't go and stand next to his visitor, however much he might have wanted to, because he hadn't stood out there when the Republican candidate, John McCain, visited in March.
Yesterday's encounter was billed as a chance for the two men to get to know each other on first-name terms. But Gordon knew that having a mate with the glamour of Barack might increase even his political pulling power. So he really didn't need his old rival Tony Blair muscling in on the visitor, having breakfast with him at his hotel. But an even bigger nuisance was David Cameron, the Conservative leader, who had persuaded Senator Obama to take a little walk – and photo opportunity – at the Palace of Westminster. They would look like a prime minister and president in waiting.
What would Gordon do? He gave his visitor orange juice and biscuits on the terrace. They got on OK, so went for an impromptu walk of their own: out the back door and across Horse Guards, followed by a few photographers and a chunky battalion of security guards to keep startled promenaders at a distance.
Afterwards Barack said their chat had been "wonderful". But after the euphoria of Berlin and the glory of Paris, his Washington entourage was shocked to be made to sit outside on the tarmac. One said the White House would never be allowed to look as tatty as the grimy No 10. In one window the nets had been pushed aside for a cardboard packing case. The symbolism was unfortunate.
The senator talked about Afghanistan and Iraq, climate change and the credit crunch, saying some problems were best solved together. Was there still a special relationship? "Absolutely." He paid tribute to British troops. Then he seemed to lose interest.
Dave was waiting a short drive away, to walk him round Parliament as if he owned the place already. They compared their busy schedules and dreams of the beach, before Senator Obama left for home, carrying the gift of a box of CDs by British bands, including The Smiths. Gordon and Dave were left behind, to fret over who had taken most reflected glory from the visit of This Charming Man.
Will you be my best friend? Please?
07.30 Tony Blair arrives at Barack Obama's hotel, The Churchill, in Marble Arch. Over breakfast, the former PM and Middle East envoy gives the senator an all-important photo-op that will play well back in the States. For Mr Blair, it's a chance to be seen with the man of the moment as his own profile is diminishing.
09.00 Gordon Brown greets Obama at Downing Street for talks, but the handshake takes place behind the door of No 10. Brown takes Obama on a tour of the building, the rose garden and even for a stroll to nearby St James's Park. It's a welcome break to be photographed alongside an emerging world statesman.
11.30 David Cameron meets Obama at the House, points out Big Ben and Westminster Hall, before more than an hour of talks in his office. He gives him a box of CDs, including Duffy's 'Rockferry' and The Smiths' 'The Queen is Dead'.