The emergency meeting was organised by the Not For Sale Coalition, a group formed to oppose the club’s takeover by US business tycoon Malcolm Glazer, who last month tightened his grip by taking control of more than 75 per cent of Manchester United’s shares.

Part anti-corporate protest, part Man United get-together, this was a red meeting in every sense. But missing from the anxious crowd was the club’s trademark red strip, normally typical bank holiday wear for dedicated fans. Why weren’t the troops in uniform?

‘As long as our club’s owned by Glazer, I’m not wearing any official kit,’ vowed one young speaker, to cheers of support. Outside the theatre, fans handed in their old replica strips and trainers as part of a ‘Nike amnesty,’ a charity collection of clothing made by the club’s official kit manufacturer, which as its biggest corporate partner is a major target for the anti-takeover campaign.

Boycotting official merchandise is a key strategy for the activists, who have begun making their own anti-Glazer range, including black wristbands and skull-and-crossbones t-shirts. Some are making the ultimate sacrifice of not renewing their season ticket, a wrench likened by one supporter to going through a painful divorce.

Those who can’t bear to give up their United habit are planning to do their bit by eschewing the traditional half-time refreshments, a big earner for the club. ‘When you’re at Old Trafford, if you see someone buying a pie, just say to them: “You’re paying Glazer’s debts there, mate,”‘ urged one coalition leader to the packed theatre.

This was a grassroots event for football lovers rather than full-time political anoraks, and the dozens of banners on display had been recycled from the terraces rather than the latest Stop the War march. Even a prominent ‘Hasta la victoria siempre’ banner, with the Cuban flag hanging above it, was in United’s black and red colours.

Andy Walsh, who chairs the coalition, said that it brings together a full cross-section of supporters:

‘Its rooted in ordinary people coming together to do something about what’s happening to their club. Some of the most fervent campaigners would describe themselves as Thatcherites, while others are socialists. The campaign isn’t party political at all. Even amongst the leadership, most are not really political activists.’

But the campaign is inevitably politicising the fans, says Walsh: ‘People are getting a harsh exposure to what football has become. Their eyes have been opened to the way that things work, and the role of business in all this.’

Fans seem to be taking to direct action with ease. One member of the audience urged a campaign of stink bombs on the terraces, while a woman’s suggestion of a topless protest was met with the kind of enthusiasm normally reserved for an injury time equaliser. For the fans who haven’t given up their tickets already, next season at Old Trafford could be a lively one.