Prince Charles, the heir to the British throne, was on hand on Tuesday evening to greet Bush and his wife before they boarded the US presidential helicopter for Buckingham Palace, where they will stay as personal guests of Queen Elizabeth II.
Opponents of the Iraq war have launched a series of protests.
The first protest was staged in central London just as Bush’s presidential Air Force One touched down at Heathrow Airport. Under the Burning Planet banner, about 1000 demonstrators, voiced their opposition to US environmental policy.
The protests will culminate with a street march on Thursday past parliament and Downing Street which organisers have vowed will attract 100,000 people.
Prince Charles (L) greets Bush as
the latter starts a four-day visit
The demonstration will end at Trafalgar Square with the toppling of a papier mache Bush effigy - a gesture inspired by the televised destruction in April of a Saddam Hussein statue by US troops in Baghdad.
"We fully expect that over the next three days the true view of the British people will become evident," said Lindsay German of the Stop the War Coalition, which led a million-strong march against the looming Iraq war in February, five weeks before the conflict began.
London's mayor Ken Livingstone, a supporter of the anti-war movement, has called Bush “the most dangerous man on the planet” and said that, even if asked, he would refuse to shake hands with the American leader.
"Bush is the most dangerous man on the planet"
Mayor of London
He also said the protesters "have the moral high ground", and cautioned that "protests must be peaceful and within the law".
Livingstone is holding a peace party in the City Hall on Wednesday, attended by many groups opposed to the war in Iraq.
Faced with both the protests and a heightened state of alert against a feared attack, police are deploying no less than 5000 officers at any one time during the visit.
Hundreds of armed US Secret Service presidential bodyguards are also in London and commercial flights over the capital are being rerouted.
Bush's trip to Britain coincides with a new poll in the United States suggesting that his popularity is at an all-time low among American voters, just a year before the next presidential elections.
Forty-seven percent of respondents to the USA Today/CNN/Gallup Poll disapproved with the way Bush was handling his job, according to the survey among 1004 adults conducted last week.