A series of events will be held in next month to mark the 10th anniversary of the huge anti-war protests, when millions of people took to the streets to voice their opposition to military action against Iraq.
Organisers of the demonstrations in February 2003 estimated that over two million people took part, with many not even making it to the start of the main march in central London because of the huge numbers involved.
Students, pensioners and families joined veteran anti-war campaigners in a day-long protest, which failed to halt the conflict in Iraq from exploding into war.
A conference will be held in London on February 9 to discuss the aftermath of the war, organised by the Stop the War Coalition.
Convener Lindsey German said: "Ten years on, the British government has learnt nothing from the war in Iraq. Troops are dying in an unwinnable and unnecessary war in Afghanistan.
"Foreign Secretary William Hague is itching to attack Syria and Iran.
"It is the ordinary people of these countries who pay the price for war, and people in Britain are being told to put up with austerity, health and benefit cuts at home while there is unlimited money for wars abroad.
"As millions around the world predicted, the war on terror has caused catastrophe from Afghanistan and Pakistan through Iraq and the Middle East to Libya, Somalia and beyond.
"The conference will bring together leading activists and commentators to analyse continuing Western aggression and how to confront it."
The 2003 protest was estimated to be the biggest demonstration ever held in the UK, leading to critics describing subsequent marches as being poorly attended even though thousands continued to take part. Protests were held in cities across the world in February 2003.