Security for the visit of US President George W Bush to London will be "unprecedented", according to Britain's most senior police officer.
Mr Bush was looking forward to his 'historic' stay at Buckingham Palace
The £4m blitz will involve all Scotland Yard's armed units and up to 5,000 officers, Metropolitan Police Commissioner Sir John Stevens said.
"The bubble" - a ring of 700 of Mr Bush's own secret service agents - will also surround Mr Bush.
The president will arrive on Tuesday for a four-day visit.
PRESIDENT BUSH'S ITINERARY
Tuesday 18 November - Arrives and receives private welcome at Buckingham Palace
Wednesday 19 November - Meets Michael Howard and Charles Kennedy, gives speech on transatlantic alliance and meets UK families of 11 Sept victims before attending royal banquet with Queen
Thursday 20 November - Meets British soldiers who fought in Afghanistan and Iraq, holds meetings with Tony Blair at Downing Street and hosts dinner at US Ambassador's residence
Friday 21 November - Travels to Tony Blair's Sedgefield constituency to meet members of the public before returning to Washington
Mr Bush has said he hopes to talk to the bereaved families of British soldiers killed in Iraq.
But protesters against the Iraq conflict are determined Mr Bush will hear their opposition.
Sir John said: "We have to accept the circumstances around the event next week are unprecedented.
"The security is unprecedented because one, the level of terrorism threat and two, the nature of the president's visit."
Tens of thousands of people are expected to protest next Thursday during the president's visit, with organisers hoping to march past the House of Commons.
Leaders from anti-war group Stop The War Coalition met police on Friday but no specific route has been agreed. They will meet again on Monday.
Lindsey German, from Stop the War, said: "We insist on our right to protest democratically and we are confident that we can reach an agreement."
Mr Bush was unfazed by the prospect of protests during his visit.
In interviews with UK journalists, he said: "I can understand people not liking war, if that's what they're there to protest. I don't like war."
Mr Bush lavished praise on Tony Blair, his "smart, capable, trustworthy friend".
"I admire him as a strong leader. He tells you what he thinks and he does
what he says he's going to do.
"And that's about as high a compliment as I can
pay a fellow leader," he said.
During the course of his visit the president is expected to have a private meeting with the families of some UK troops killed in the Iraq conflict.
When asked about the families of the 54 British soldiers killed in Iraq, President Bush said: "I am going to meet some.
"There's two messages. One, the prayers of the American people and the prayers of the president are with them, as they suffer.
"Secondly, that I will tell them that their loved ones did not die in vain."
The father of Corporal Russell Aston, who was killed in June when he and five other soldiers were attacked by a mob near Basra, said he had no intention of meeting the president.
"I have nothing to say to them," Mike Aston said.
"My son is gone. He went to war on the 14th of February and I will have to get used to the fact that I will never see him again.
"To actually to come face to face with the perpetrators of that war would give me a great deal of anger. I want nothing to do with it."
However, the widow of Sergeant Steven Roberts said she believed her husband had not died in vain.
She hoped to gain "insight" by meeting someone face to face and "looking them in the eye".
"I would like to know if 'shock and awe' was the last resort or were there any other options that they could have done rather than the way they actually did it," Samantha Roberts said.
Sgt Roberts, a Desert Rat, was the first British soldier killed in the Iraq war.