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It says a lot about a man, how he makes his big entrance. A motorcade says brute power, as everyone stops to make way for The Leader and an arrival that no one can ignore. But a helicopter out of the night sky? An other-worldly presence coming down out of the starry heavens, bright lights cutting through the darkness as the divine presence comes down to earth?

That is how Barack Obama arrived in London last night, with a deafening chugga-chugga of helicopter engines as he landed by the US Ambassador’s residence in Regent’s Park. This is how the Second Coming will be, if the Lord chooses to make His appearance in a VH-3D helicopter fitted with anti-missile flares.

Only an American president can make such an entrance. Not only would it be grandstanding with anyone else, but other countries do not have the advantage of an ambassadorial residence set in 12 acres of prime London parkland. Landing a helicopter in Mayfair or Kensington just isn’t the same thing.

Down below, a small crowd of the faithful craned their necks to get a better view. “Is that him? Is that him?” asked someone excitedly. A girl in the crowd took a photograph with her mobile phone: she wasn't too sure, and at that distance a helicopter is just a helicopter, but you cannot be too careful.

They were not the only ones being careful. Dozens of police were on duty around the residence, Winfield House, and in the absence of crowds of protesters they were questioning, under the Prevention of Terrorism Act, anyone who looked in the slightest bit suspicious.

One young man, Joe, who works in an advertising agency nearby and had made a detour on his way home to see the arrival, made the mistake of having a beard. That earned him a searching, and a docket from the police confirming that he had been questioned and released without further action. “We were having a discussion before whether it was cool to be seeing Obama, or really sad to be waiting for him,” he said. “I think it has just gone over the boundary from cool to sad.”

If Joe was more of an idle passer-by, others were more committed. Emily Gee, originally from Charlottesville, Virginia, but now working in London for English Heritage, said: “Obama is just great. We wanted to be part of it when he is in London. I had a big party at my house on inauguration night, and I wanted to carry on the theme.

She had an Obama badge strung round her neck, and a Stars and Stripes flag to wave when the presidential helicopter landed. “I’ve got an Obama Mama T-shirt in my bag,” she said, “but I thought that was maybe a little too much.”

With her was Benedict O’Looney, 42, an architect from Peckham in South London who spent much of his childhood in Delaware. He said: “We are here because we are so relieved that there is now a breath of progressive wind blowing over from the United States. It’s the least we could do to be here and say, ‘Yeah!’.

Saying yeah was about all they were going to do: strict security measures ensured that no one was going to get close to the residence. A perimeter fence was erected around the grounds with officers in high-visibility jackets stationed every 50 yards.

Then came the helicopters, one after another. First a Chinook flew in from Stansted airport. No one in the crowd was fooled by that, not even the excitable young students from Syracuse University who are studying in London for a term.

Another helicopter came, and another, and no one seemed too sure what was going on until the helicopter arrived that everyone knew was Marine One. It was big, it was noisy, it had bright lights. It was undeniably important.

“It was amazing,” said Jenna Jabinsky, one of the Syracuse students. “It was really cool. We took a lot of blurry pictures, but at least we’ve got something to tell our friends and family.”

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