US President George W. Bush has arrived back in the US following his controversial trip to Britain.
Mr Bush spent three nights at Buckingham Palace as guest of Queen Elizabeth, was honoured with a 41-gun artillery salute and a parade of soldiers.
But suicide attacks in Turkey on Thursday - with Britain's top diplomat in Istanbul among the 27 dead - turned the visit into a crisis summit. Hours later, more than 100,000 anti-war demonstrators poured into the streets of London, toppling a statue of Mr Bush in an echo of Saddam Hussein.
Both Mr Bush and British Prime Minister Mr Tony Blair vowed that the attacks in Istanbul, which struck the British consulate and the office of Britain's largest bank, would only reinforce their determination to stand shoulder to shoulder against terrorism and in Iraq.
The attacks were widely blamed on al-Qaeda militants and suspected to have been a strike on America's closest ally that was timed to coincide with Mr Bush's visit.
"I'm fortunate to have a friend like Tony Blair. America's fortunate to have friends like the people of Great Britain," Mr Bush told reporters at a sports school in Sedgefield, the small country town Blair represents in parliament.
"The people of Great Britain have got grit and strength and determination, and are willing to take on a challenge. And we're being challenged. We're being challenged by killers, cold-blooded killers. And we're going to prevail."