By Ryan Dilley BBC News Online

Perhaps as many as 400,000 people flooded into Central London to protest against military action to remove Iraqi leader Saddam Hussein from power. Brian Haw remains unimpressed as tens of thousands of people descend on central London to join a march protesting against any attack on Iraq.

The father of seven has spent the past 486 days and nights proving his passionate disapproval of sanctions against Iraq and the Anglo-American bombings by camping outside Parliament.

Brian Haw: 'It's my children, my brothers, my sisters dying in Iraq'

"The marchers shouldn't have just one day out in the sunshine. They should stay until what's happening to Iraq stops and not just go back to their families and comfortable homes."

Those seeking the march's marshalling point stop at Mr Haw's camp for directions. One woman asks if she can stand with him for a while. "I can't go to the march," she says, "I have to be somewhere else at 1.30."

Others more willing to give up a full afternoon for the demonstration are streaming out of the nearby Tube station, along with tourists eager to see Big Ben.

Lone voice

American visitor Nels Hefty is having a heated conversation with one of the many people selling the Socialist Worker paper.

"I have a hard time understanding why these people oppose removing Saddam Hussein. They all just admitted he was a nut, so to argue that he should stay in power is absurd."

A native of the liberal San Francisco Bay Area, Mr Hefty is used to dissenting voices, but he is sure "people are in denial" over the threat posed by the Iraqi leader.

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"There's no doubt in my mind that once he has nuclear weapons to strike at the US or Israel - even smuggled there in a suitcase - he'd use them."

Mr Hefty's views are quite literally drowned out. A marcher fires up his loud hailer to chastise the laggards in his contingent: "CND keep up! You at the back, CATCH UP!"

The hectoring over, he begins a chant to the tune of pop hit Who Let the Dogs Out? "Who let the bombs drop? BUSH, BUSH and BLAIR!"

At the demo's starting point by the Thames, such words of condemnation must compete with commerce, as traders noisily hawk anti-war merchandise.

Buy the T-shirt

T-shirts showing President Bush in cowboy garb and Tony Blair as a loyal poodle are going for �10. Whistles can be had two for �1.50.

The screech of whistles adds to the problems of those trying to meet up with friends in the unexpectedly dense throng.

"We can see the banner," a woman bellows into her mobile phone. "Are you near the banner?"

David and Melissa Warner: 'Our quarrel isn't with American people'

While it is clear the march has attracted seasoned demonstrators - with their practised chants and well made banners - many of those present are new to public protest.

"I've never demonstrated before," says distinguished actor David Warner, "that shows how important I think this issue is."

Accompanied by his American daughter, Melissa, Mr Warner says he doesn't "want to see Iraqi civilians killed or our young people sent there to get killed. My quarrel is not with the American people".

American allies

American marcher Erin Berquist says there is just as much disquiet about military action against Iraq on the other side of the Atlantic.

"People here don't understand that a lot of Americans don't want a war either."

Despite their serious message, many marchers are in high spirits. William Wynter and Rowyda Amin blow out an enthusiastic tune on pipes, their faces painted with peace slogans.

Adrian May: "It's not democracy to say who can run another country"

"I'm from Saudi Arabia," says Ms Amin, "and I'm really worried about the stability of the whole Middle East if Iraq is attacked. I don't think people have thought about the consequences."

Adrian May has dressed up as Darth Vader. "It's not democracy to say a country with lots of weapons and money can decide who rules another country," he says through his mask, "That's not to say I like Saddam or that I particularly dislike Bush."

As the marchers file along the Thames, beside Parliament and Mr Haw's camp and towards Trafalgar Square - it becomes clear that many of Mr May's fellow marchers do dislike the US president.

Peaceful protest

Chants and placards dubbing Mr Bush a terrorist and a Nazi fill Whitehall. However, few taking part in the demonstration seem filled with rage.

Had there been angry scenes, central London contains many relics of past military campaigns which have proved tempting targets for vandals during previous protests.

William Wynter and Rowyda Amin: 'Bush doesn't have the right to attack Iraq'

The statues and war memorials remain untouched. An Army open day at Horse Guards Parade was shut because of the march - though a police officer guarding the armoured vehicles, trucks and jeeps on show thinks that was just a precaution.

"The marchers want peace, not war," he jokes.

As the procession moves to its final destination in Hyde Park even the novice marchers are getting the hang of the chants.

"What do we want?" shouts a man with a loud hailer. "Justice!" the crowd replies almost in unison.

"I just want to get to work," says a man grumpily battling against the flow of the march.