Anti-war campaigners have accused ministers of caving into American pressure by keeping protesters well away from a reception for George Bush in Downing Street tomorrow.
As the outgoing US President sits down for dinner with Gordon Brown, demonstrators will be one-third of a mile away in Parliament Square. A major police operation will be mounted amid fears that demonstrators will try to break through a security cordon around No 10.
An application by protesters to march down Whitehall and past the gates to Downing Street has been rejected by the Metropolitan Police.
Chris Nineham, a spokesman for the Stop the War Coalition, said: "The Americans want a photo of George Bush's cavalcade without the protesters being there. There's no question the UK Government has gone along with it, which is extraordinary considering the unpopularity of George Bush in this country."
Chris Huhne, the Liberal Democrat home affairs spokesman, has written to Jacqui Smith, the Home Secretary, calling for the march to be allowed. He said: "In this country we have a long tradition of peaceful protest and I would be shocked if British civil liberties were curtailed at the request of a foreign government."
Thousands of demonstrators are expected to gather in Parliament Square tomorrow. They are being asked to bring drums, trumpets, whistles, sirens and horns in an attempt to make themselves heard by the President.
Scotland Yard said it had not banned the march as plans to close Whitehall for "good public safety reasons" had already been drawn up before it received the application. A spokesman added: "We have had a number of meetings with the Stop the War Coalition where we have made it expressly clear we will facilitate all lawful protest within the constraints of our security operation that will be in place."Reuse content