By 11am on Monday, they were already turning people away from the Black-E, a former congregational chapel on the edge of Liverpool's Chinatown, about 10 minutes' walk from the Labour Party conference.
This was The World Transformed, a parallel festival run by Momentum, the left-wing group set up to support Jeremy Corbyn's leadership, which is viewed with horror and suspicion by most of the party's MPs.
“Don’t worry, we’ll be here for another couple of days. Come back again,” a young steward was telling a couple of disappointed late arrivals.
Upstairs, there were stalls selling books and T-shirts ("Still hate Thatcher", said one) and serving coffee and snacks. While, in the basement, the former BBC and Channel 4 journalist Paul Mason was leading a discussion about the lessons the Labour Party could learn from the social movements that have sprung up around the world since the economic crash of 2008.
Mason, who left Channel 4 this year to escape the constraints of political impartiality, showed videos from the 2013 Gezi Park demonstrations in Istanbul and spoke about the transformative impact of social media and smartphones on political activism.
But first he asked us to form small groups to discuss how Labour might act differently if it were to become a social movement.
I was with Jack, a fresh-faced young man in his 20s, and Maggie, a veteran campaigner in her 60s who said she sold the Socialist Worker, the newspaper of the Socialist Workers Party, every Saturday.
Maggie suggested that Labour should make its offices in towns and cities all over Britain available to campaign groups when they were not being used for party business.
Jack wanted Momentum to follow the lead of left-wing groups elsewhere in Europe by taking autonomous action to benefit poor communities, setting up food banks and childcare groups.
“Momentum needs to move beyond being defined by fighting over the leadership,” he said.
These sentiments were echoed when the discussion opened up to the floor, with one man calling for Momentum to embrace the “propaganda of the deed” by exemplifying the society it wanted to create.
“I think most of us here are probably of an age when our street-fighting days are over,” he said. “There’s so much social need there. Rather than discussion groups, we should get people together to start helping.”
Keeping up pressure
Mason said Momentum had an important role to play now that Corbyn has been confirmed as leader, not least in keeping up pressure on the Labour Party hierarchy.
“I don’t want to see Momentum become a parallel hierarchy to the Labour Party,” he said. “But we have to use it to fight the purge, which is carrying on, fight for the policies, which they don’t want to have even on the conference floor, and to bring [on] a new generation of MPs, who, I would argue, can replace the ones who don’t get it.”
Over at the Labour conference, Len McCluskey, leader of the Unite union and a Corbyn ally, was telling MPs who did not support Corbyn that they should quit.
"I say to the merchants of doom, in the words of Shakespeare's Henry V, if you have no stomach for this fight, depart the battlefields," he said.
Shadow chancellor John McDonnell was more conciliatory in tone, but he signalled a dramatic departure from Labour’s economic policy during the Blair years.
It was time, he said, for government to take a bigger role in industrial policy and to shift the tax burden away from income and on to wealth.
"My dad was a Liverpool docker and my mum was a cleaner who then served behind the counter at British Homes Stores for 30 years. I was part of the 1960s generation," he said.
“As a result of Labour government policies, I remember the day we celebrated moving into our council house. My brother and I had our own bedrooms for the first time.
"We had a garden front and rear, both of us were born in NHS hospitals, and both of us had a great free education. There was an atmosphere of eternal optimism."
And in words which would turn the stomachs of diehard Blairites but which earned him a standing ovation in the conference hall, McDonnell told delegates that his vision for a fairer future not only had a shape but a name.
“In this party you no longer have to whisper it – it’s called socialism,” he said.
