After the twin tower attacks, a military band broke with tradition and played the US national anthem at the Changing of the Guard ceremony at Buckingham Palace. Less than 18 months later, one million people took to London's streets to protest against the forthcoming war in Iraq.
Now with President Bush heading to Britain to see Tony Blair for what should have been a triumphal reunion with his closest ally, the 200,000 Americans living in London are reflecting on how times have changed.
They recall with wonder how the British dropped their innate reserve after the attacks on 11 September 2001. But now, after wars in Afghanistan and Iraq where Britons and Americans fought side by side, they face a wave not of anti-Americanism but anti-Bushism.
Honeymoon is over
Christine Swanson, back home after taking the kids on the morning run to school, said: "I am frustrated. As horrible as 11 September was, it was a real opportunity to move forward in a positive way. There was a lot of goodwill to tap into and it took the incredible talent of George Bush to piss it all away in two years."
Almost 25 years after she first called London home, Pennsylvania-born Virginia Schultz vividly recalls the days after 9/11.
"People were hugging me in the street. I thought the way they reacted then was wonderful. Right now there is strong anti-Americanism and I compare it to the Vietnam War. Bush has been targeted as the villain in all of this. I think he is even more unpopular than Nixon was."
Americans say it is tough living in
UK due to anti-Bush sentiments
The New York Times' London correspondent Warren Hoge told Reuters: "America is now something of a rogue state, a pariah nation. People repeatedly say it isn't Americans we don't like, it is just Bush.
"He pushes hot buttons. Bush has so much to do with this rather stupendous fall-off in American popularity. It is quite amazing to think where we were the day after 11 September and how much of that goodwill has been squandered."
Film-maker Paul Berczeller, a New Yorker now living in London, agreed: "The groundswell of goodwill has definitely evaporated. It was a real missed opportunity. As an American living in Europe, I have to explain back home how negatively Americans are viewed in Europe."