More than 50 years ago, in the wake of the Second World War, London's Methodist Central Hall was used as the venue for the first general assembly of the newly formed United Nations.
Organisers said 1,000 delegates were at the meeting
The meeting saw the creation of the UN Security Council, which may in the next few days make a momentous decision affecting the future course of the crisis over Iraq.
The irony, then, of the Stop the War Coalition seeking to leave its own legacy on the historic building did not go unnoticed as the organisation launched its People's Assembly for Peace on Wednesday.
Indeed, one of those in the audience in 1946 when prime minister Clement Attlee welcomed delegates to the new UN was a young Tony Benn.
And on Wednesday, Mr Benn was among the speakers as the coalition "challenged the government's authority to wage a war with Iraq" and mapped out its future course in the face of what most attending felt was the inevitability of conflict in Iraq.
(Tony Blair) has released us from our moral obligation to accept decisions and we are now free to follow our consciences
Mr Benn said the coalition could take heart from the "tremendous confidence people have that we don't have to accept everything that is being done".
Calling for "the restoration of democracy in the UK and the restoration of international law", he said Tony Blair was behaving like a "medieval king".
By doing so, the prime minister had "liberated" those opposed to his stance on Iraq, said the former cabinet minister.
"By by-passing all these democratic procedures, he has released us from our moral obligation to accept decisions and we are now free to follow our consciences," said Mr Benn.
Rail union boss Bob Crow urged delegates drawn from trade unions, religious groups, schools, political parties and peace groups to embark on a campaign of civil disobedience, blocking roads and putting up anti-war candidates in May's elections against any councillor backing the government's stance.
And a group from a London school won wild applause as one-by-one - with the exception of one bashful youth suffering from stage-fright - they set out their reasons for opposing war with Iraq.
Benn: "This is just the start"
"The war is just killing people for no reason," said one. "The US is only on this war for Iraq's oil to protect its own financial interests," said another. "This war is immoral and it really shouldn't happen," added another.
Organisers said around 1,000 people had registered to "sit" in the assembly as it opened a stone's throw from the heart of Parliament on Wednesday morning.
Delegates were told by Stop the War chairman Andrew Murray that the meeting was not "just another anti-war rally", but that it must look ahead to agree on future action against any conflict.
There are calls for a strike - either for an hour or for a day - if war breaks out, forms of "non-compliance" and more marches and demonstrations.
And while the mood among delegates was one of resignation as to whether a war will take place, there was no sense of the anti-war campaign petering out.
Central Hall has hosted historic meetings
"I don't think we will stop the US but I think we are seeing the beginnings of the breaking up of US hegemony because there is such a movement throughout the world and with the most unlikely people," said Isobel McMillan, from south London.
"It may be the dawning of a world where people are actually valued, humanity is valued," she added.
Jim Warner, an NUT delegate from the West Midlands, said an agreement on a second UN resolution would be a "fudge" which while reducing the impact of the anti-war movement would not stop it in its tracks.
"Events like today are bringing together the various coalitions from around the country in order to give confidence to the collective feeling that they can generate opposition to what's going on," he said.
And according to Mr Benn, there is no shortage of confidence in the anti-war movement. Indeed, he said the movement now had "the confidence we have lacked for too long to chart a political course for us".
Saying UK troops may soon "be ordered to commit war crimes", he went on: "This is not the moment when we give up -this is the moment when we really start."
The great majority don't want any part of George Bush's war and we are determined that we will be heard
Stop the War coalition
The demonstration in London in February, along with others around the world, had been "the largest demonstration there has ever been in the history of the world".
But that world now faced "a period of acute danger", he said.
"But we can look forward with renewed confidence and renewed hope. We have to support the idea that it can be done, that another world is possible.
"If we do I don't think there is any power in the world that will be able to stop us."
Earlier, Mr Murray, hailing what he said was "a historic day in our developing mass anti-war movement", told delegates that the assembly was important because "the British government is not speaking for the British people".
People have got to start putting their money where their mouths are because you won't get a second chance - we have a duty to defend the human mankind
"The great majority don't want any part of George Bush's war and we are determined that we will be heard," he said.
The prime minister's "moral argument" for action was "the morality of imperialism", he said, adding that a future campaign slogan may be: "Stop the war - sack the prime minister".
He urged MPs doubting the government's stance: "If you are searching for your conscience, please find it now."
That message was echoed by Mr Crow: "People have got to start putting their money where their mouths are because you won't get a second chance - we have a duty to defend humankind."