Under slate gray skies, the protesters gathered at Hyde Park and then marched through the heart of the city to Trafalgar Square, where speakers talked from the base of Nelson's Column, a monument to a past war and a frequent site of peace gatherings.
"This is a place where movements are born, and we are building a world peace movement," said Tony Benn, a former Labour Party Member of Parliament and frequent critic of Prime Minister Tony Blair's government.
Despite headlines telling of Northern Alliance triumphs and late reports suggesting Osama bin Laden's capture is imminent, criticism of the war Sunday was as fierce as it has been throughout the military campaign. Estimates of the crowd size ran from 10,000 upwards.
At Hyde Park, the marchers assembled near the famous Speaker's Corner, where diatribes against the powers-that-be are a weekly rite.
The talk this Sunday related the effort against the war to the wider movement against the globalization, poverty and imperialism and linked an end to terrorism to the resolution of the Israeli-Palestinian conflict.
Signs revealed the breadth of opinion under the anti-war umbrella, with slogans from "Not In My Name" and "Stop This Bloody War" to "Bikes For Peace." Trade unionists and Quakers stood beside groups with anarchist and communist platforms.
One small group of young Muslim men carried posters decorated with bin Laden's picture. "Be Aware, America. When our time comes there will be no mercy," read one.
But many of the speakers and most in the crowd condemned the Sept. 11 attacks.
Many acknowledged there were no easy answers to the problem of terrorism, but said their concern was that the world would think the success of the bombing campaign to date meant an end to suffering in Afghanistan.
Some pointed out that Saturday saw the heaviest bombing yet, despite the recent victories on the ground. Distrust of the Northern Alliance was deep.
"America's action has allowed a group of warlords and criminals to take power in Afghanistan," said Sophia McGiven, a London resident.
"They're already fighting as to who should be in control," said John Haylett, editor of the socialist newspaper The Morning Star. Haylett said instead of bombing, the United States should have given aid to Afghanistan, reversed its policies in Palestine and Iraq, and backed an International Criminal Court to try people like bin Laden.
Dave Nellist, chairman of the Socialist Alliance, said that he could not support a war waged with "bombs so smart they can hit the dead center of a Red Cross center not once, not twice, but three times."
Speakers also slammed moves to change civil rights laws in the wake of the attacks on New York and Washington.
"We had the most draconian laws on terrorism already befor September 11 in the whole of Europe," said Louise Christian, a civil liberties lawyer. "There is no use fighting a war against terrorism if we support...state terrorism."
Britain's Home Secretary, David Blunkett, has declared a state of emergency in the UK to allow the government an exemption from the European Convention on Human Rights so it can detain suspected terrorists without trial.
Benn, the elder statesman of Britain's left-wing, blasted that move and the Bush administration's push for military trials. "This is a fight for our freedom and the freedom of the people of the world," he said.
Quoting Martin Luther King, Dr. Mohammed Khan of the Association of Afghan citizens in Britain said, "We must not allow our creative protest to degenerate into physical violence," and said he feared the war would lead to "thermonuclear destruction."
As the group marched toward Trafalgar Square, the thunder of drums and the moan of horns echoed down the streets of one of London's busiest shopping districts, and a sea of colorful signs flowed down the broad avenue Piccadilly between Victorian-style buildings of dingy concrete.
A ghastly sculpture danced above the marchers heads, depicting Mr. Bush and bin Laden as the heads of a grotesque beast with bloody claws.
Some marchers took a simpler, lower-key approach. Imaan Ali, a native of Pakistan who lives in London, said she came to the march because the war is "killing the kids and killing the poor people."
"Two wrongs don't make a right. Of course I'm against terrorism. The fundamentalist Muslims are the worst people," she said, but added that ordinary citizens "are the people who are being killed."
At the same time, Blair was mocked for being no more than "a foreign ambassador to the United States" with a willingness to let British troops do America's "dirty work."
Although supported by all three major political parties, the war has been debated fiercely in Britain.
Left-wing members of Blair's ruling Labour Party have criticized the military action, television programs have featured heated arguments between hawks and doves and London's multitude of newspapers have sparred over the issue daily.
Most Britons support the war, according to opinion polls. But even those who back the bombing are worried that the United States' motives might differ from Britai's.
That concern apparently runs to the highest echelons of government: The Sunday Times reported that British leaders are upset that the Bush administration is focusing on the capture of bin Laden rather than diplomatic and humanitarian efforts.
There are links among the British peace groups and their less-visible American counterparts.
Between speeches at Nelson's Column, an organizer read an email he had just received from the Berkeley Stop the War Coalition. "We feel confidence and strength to part of an international community. It's nice to know you're out there."
By Jarrett Murphy
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