World reflects on 2003 Iraq war
London’s rally has been organised by the Stop the War Coalition, CND and the Muslim Association of Britain.
Demonstrators will leave Hyde Park at 12:00 GMT and march to Trafalgar Square.
Mayor of London Ken Livingstone, anti-war MPs George Galloway, Alice Mahon and Jeremy Corbyn, RMT union leader Bob Crow, and others are set to address the rally.
Lindsey German, of the Stop the War Coalition, said: “We are continuing to march because we want to make clear the strength of anti-war feeling in this country.
“Everything we said about the war has turned out to be true and everything the government said has turned out to be a lie.
“The tragic events in Madrid show clearly that we are not safe from terrorism.”
Kate Hudson, chairwoman of CND, called for politicians to pause for reflection before the world slips “into a cycle of violence.”
“Every day more and more people are convinced by our arguments,” she said.
“We reiterate our call for a full public inquiry because the public has a right to know why we were taken to war.”
Meanwhile, foreign secretary Jack Straw told The Telegraph today that despite the Madrid rail bomb atrocities, the world was winning the war on terror.
Mr Straw said unilateral “pre-emptive” US-led military action to oust Saddam Hussein from power – to which Britain was the first supporter – was a “rational and effective” strategy.
Across the pond, US President George W Bush said the US-led invasion of Iraq was a “day of deliverance” for Iraqis.
In a speech to diplomats and officials from 83 nations given in the White House East Room, Mr Bush said there was no neutral ground in the war on terror.
Mr Bush said: “No concession will appease their [al-Qaeda] hatred. No accommodation will satisfy their endless demands. Their ultimate ambitions are to control the peoples of the Middle East and to blackmail the rest of the world with weapons of mass terror.
“Any sign of weakness or retreat simply validates terrorist violence and invites more violence for all nations. The only certain way to protect our people is by united and decisive action.”
The Iraq war has cost the US dear in lives and political diplomacy. More than 500 US soldiers have died since hostilities broke out in March.