UK protests: Mounted officers augmented police lines in Whitehall last night as a growing demonstration outside the Westminster parliament protested at the news of land war under way in Iraq.
And a wave of protests swept across Britain ahead of the address by the Prime Minister, Mr Tony Blair, address to the nation while B52 bombers were loaded at RAF Fairford and as news reports confirmed that British Royal Marines had stormed into southern Iraq.
For most of the day a crowd of workers and college and school students - sometimes estimated at up to 2,000 strong - had prevented traffic passing through Parliament Square.
At one point some 50 teenagers staged a sit-down protest in the square, but were later persuaded to continue their protest on the grass verge under the shadow of the statue of Sir Winston Churchill.
Police later drew their truncheons as a section of the crowd tried to force their way into Whitehall and gain access to the gates at Downing Street.
By early evening the character of the crowd had changed and swollen to an estimated 5,000, causing police to push back their cordons and spreading the disruption into the surrounding area.
The peace campaigner, Bianca Jagger, addressed the demonstrators at one point telling them that the war would spell humanitarian catastrophe for the people of Iraq.
Around 1,000 demonstrators of all ages gathered in Glasgow city centre, and there were demonstrations too in Suffolk and Swansea, where hundreds of pupils at Olchfa Comprehsnive School staged a sit-in after being prevented from joining a protest in the city.
Pupils brought chaos to York by walking out of school and staging sit-down protests around the city. Rush-hour traffic was similarly halted in Leeds, while around 300 gathered for a second day of protests in Manchester.
An estimated 150 people marched on Sheffield Town Hall, while some 60 local pupils staged a lunchtime sit-down protest, and another 400 satdown to protest in Park Square before walking to the Peace Gardens. Hundreds also gathered at Grey's Monument in Newcastle while police closed roads in Bristol city centre where some 400 protesters assembled.
The left-wing MP, Mr George Galloway, told the London protesters they were speaking for "the great mass" of the British people. He said 50,000 school children had been on the streets of Berlin and he praised their British counterparts who had spent their day in Parliament Square.
"We are not going away," he declared. "We will protest every day. We will demonstrate until this war is stopped."