Anti-war demonstrations will continue despite the apparent successes of coalition forces in Iraq, protesters have vowed.
Anti-war protests have been well attended in London
Students gathered in Parliament Square on Thursday as the Stop the War Coalition announced plans for an anti-war march in London on Saturday.
"There is still a lot of fighting going on in Iraq," said A level student Henna Malik. "It should stop immediately."
The 18-year-old from Surrey added: "We want to stop Blair going on any more mad rampages."
Around a million people took to the streets of the capital on 15 February in the UK's biggest demonstration.
People are terrified - and the Iraqis are terrified - that this will turn into a 'new American century'
Stop The War Coalition
In the weeks since the war began, the peace marches have continued but with fewer people taking part.
On 22 March, organisers estimate 500,000 people took part in a second mass London rally.
And again on 29 March, marches were held across the UK, Europe and the US.
The Stop The War Coalition says it expects a big turn-out again this Saturday, despite the scenes of jubilation on Wednesday as American tanks rolled into Baghdad.
"Firstly, the war is not over. It's still very volatile in many areas of Iraq," said coalition spokesman Chris Nineham.
"I think people see through the triumphalism of the press and feel it is a colonial occupation.
"When you saw the Stars and Stripes on the statue of Saddam Hussein, it looked like an occupation.
"People are terrified - and the Iraqis are terrified - that this will turn into the "new American century" the hawks in the US government are talking about.
"No-one knows where Bush and Blair will stop."
Saturday's march starts at two points - Victoria and Waterloo stations - at noon.
They converge on Parliament Square where a minute's silence will be held "for the war dead".
The marchers will then progress up Whitehall for a rally in Hyde Park.