The man who, in 2008, superglued himself to Gordon Brown in protest at the planned expansion of Heathrow is trying to get people’s attention. “We need volunteers to be Charlie the gay donkey,” says Dan Glass. “Front and rear.” It’s 10.30 on Sunday morning in the Richmal Crompton, a Wetherspoon’s pub opposite Bromley South railway station. About 70 people are gathering here before heading off to Nigel Farage’s local pub in Kent – to stage a Beyond Ukip cabaret.

Glass wants people he believes Ukip targets to “get together to showcase the beauty and diversity of our global community”. He’s invited migrants, breastfeeding mothers, Muslims, NHS workers, anti-fracking environmentalists, disabled people, people from lesbian, gay, bisexual, transgendered, transsexual, intersex and asexual communities, and people living with HIV to take part. He also invited Holocaust survivor Ruth Barnett, author of the recent book Jews and Gypsies, who came to Britain on the Kinderstransport aged four, to speak at the cabaret.

Barnett’s appearance underlines the serious point behind Glass’s pranking political protest. “As the descendant of four grandparents who are Holocaust survivors,” he says. “I’m concerned about what Ukip does – it ‘others’ people. The Holocaust narrative is about how oppression and fascism creeps up by targeting and blaming communities.”

Beyond Ukip Cabaret. Photograph: Antonio Zazueta Olmos for the Guardian

He hands out flyers that state the day’s agenda: “They think we will run and hide and be sad and depressed but we celebrate our diversity. We will take our diversity to the heart of where Farage exists to show him he has nothing to be scared about. We will not succumb to their prejudice. We will create the world we want to live in. A world beyond Ukip.”

Some suggest that it’s not only Farage’s local that should experience the beauty of multicultural diversity, and Glass agrees, saying that if today is successful, they should repeat the cabaret near the prime minister’s home. “Where’s Cameron’s local pub?” he asks.

“Chipping Norton.”

“Right, we’re going there.”

And the gay donkey? A Ukip candidate in Merthyr Tydfil last December made a bizarre speech claiming that a gay donkey had tried to rape his horse. Haven’t gay Welsh donkeys suffered enough, you might ask, without having their sexuality lazily associated with sexual violence? Absolutely – and that’s why, no doubt, so many hands shoot up in response to Glass’s call for volunteers to play the donkey’s rear end.

Minutes later, we’re on two coaches heading towards Downe, the Kent village once famous as the home of Charles Darwin and now better known as Farage’s stamping ground. What my Guardian colleague Hugh Muir calls “hideously diverse Britain” is on a day trip to a mostly monocultural corner of England. There’s a man in a banana suit (Why are you wearing a banana suit? “Because Dan asked me to.”) and two men dressed in tweed caps and wellies, representing a new group called Farmers against Fascism. There’s a performance poet, an anti-Ukip standup and quite a few young men in shorts looking forward to singing It’s Raining Men at the cabaret’s denouement.

As we drive through bucolic Kent, some on the coach tweet their support of the cabaret to #UKIPcon, while disabled rights activist John McArdle, co-founder of the Black Triangle Campaign, explains to me the plight of hunger strikers in detention centres. It’s part school trip, part fancy dress party, part political rally.

Dan has booked the function room at Farage’s local, the George and Dragon, for the cabaret, but told the landlord that the reservation is for a birthday party. The room proves far too small for the cabaret, not to mention the allied events: the Polish, Italian and Portuguese language classes, an HIV anti-stigma class, and a Gender Fluidity Fun workshop. Jamie Newman, the landlord, tells Dan that the room was booked for 30, and Dan admits that there are many more. Newman remains impressively sanguine throughout the next few hours of what is evidently not a birthday party, even when a police officer calls to ask if there is any trouble. Which, so far, there isn’t.

While the cabaret sets up, I join the UK Citizenship Quiz in the bar. Some gentlemen are watching Liverpool-Man U on a laptop. “One nil to Man U, Juan Mata’s on fire,” one of them confides to me. Excellent, but I wonder how many of the locals here could pass the citizenship test? Who was the first archbishop of Canterbury? What was the population of Britain in 2010? Name two Roman forts on Hadrian’s Wall?

Back in the function room, Zee Ahmed takes the stage and asks the audience for a little quiet so he can sing an Islamic prayer and a few suras. It’s a rather beautiful few moments, after which Dan takes the mic. “Let’s give it up for the breastfeeding mamas!” he says pointing at a row of activists. Some are women with real babies, some women with plastic breasts and plastic babies, and at least one a man. All are protesting against Farage, who last December backed the decision of Claridge’s hotel to ask a breastfeeding woman to cover up, saying that mothers should “perhaps sit in the corner” when they breastfeed. They’re all sitting beneath a framed portrait of Charles Darwin, that lavishly bearded Victorian paterfamilias, who seems to be eyeing their cleavages during the rest of the cabaret.

The gay donkey. Photograph: Antonio Zazueta Olmos

The gay donkey wends its way between cabaret artistes and their supporters in this crammed space, receiving affectionate pats and tickles. There is nearly an unpleasant incident with a spilled pint. I’m no homophobe, but that animal should have been confined to the beer garden. A spokesman for Britain’s Roma community makes a heartfelt, moving speech: “Our children are in segregated schools,” he says, welling up with tears. “They make our children stupid.”

Next, Zita Holbourne, a member of Black Activists Rising Against the Cuts (Barac), recites a poem.

“Multiculturalism cannot fail to succeed

It’s not in the gift of a politician to proceed

With its termination

It’s not your creation

It’s in our blood and in our bones

You can’t create multicultural free zones

It’s on our airwaves and in our streets.”

In the public bar, I attend the HIV anti-stigma class, run by a Spanish man wearing a bunny costume with huge floppy white ears. One participant claims that those with HIV are more healthy than those who are HIV negative because they have more frequent health checks.

Back in the function room, Dan announces that there is a huge cake lovingly baked for the cabaret by a group of HIV-positive Nigerian women, but by the time I get past the crowds of activists joining in the Dabke dancing display by Palestinian and Lebanese women, it’s been cut up and devoured.

Then there are a few difficult moments when I accept Dan’s injunction to participants to introduce themselves to a stranger. Andrew Boyd, an American who describes himself as wrangler-in-chief for Beautiful Trouble, an international network of artist-activist trainers who aim at making grassroots movements more creative and more effective, tells me movingly about his Jewish and Romanian heritage, while I struggle to find anything good about being straight, white and British. “But you have to do better,” he says. “You have to come up with a better notion of patriotism – recapture the flag, as we put it in the States, from the bigots. Maybe events like this can help.”

Many of the activists are deeply moved by the event. “It feels like an occasion of pure love,” says one man, grabbing the mic. All these people coming together, saying to Nigel Farage, ‘Why don’t you like us?’”

Soon afterwards, a rumour spreads through the room. Farage is in the Queen’s Head across the street. The activists are divided. Some want to stay and finish singing along to anti-fracking campaigner Pamela Mudge-Wood’s version of I Vow to Thee My Country (“I vow to thee, my countryside / My aquifers and lakes / To withstand against the frack machines / Earth’s life-blood is at stake” goes the stirring chorus Pam presents to us in handouts). Others are worried about leaving the function room in such a mess. But the largest contingent wants to go over to the Queen’s Head to confront their nemesis.

And so, soon afterwards, a conga line featuring an extraordinary array of different sexualities, ethnicities and outfits sashays across the street in the spring sunshine with a PA machine playing Sister Sledge’s We Are Family. What was pub cabaret has become street theatre. Before I can join the activists who rush into the Queen’s Head, Farage, looking angry and pin-striped, walks quickly from the pub into a waiting car driven, reportedly, by his wife.

Protesters try to block Nigel Farage’s car from leaving. Photograph: Antonio Zazueta Olmos

The event, which up to this moment had been good-humoured and non-threatening, becomes, just for a moment, something else. Two or three activists bounce on the bonnet of the car. Others surround it, shouting teasingly at Farage. As the car pulls away, I worry that one of the activists will fall under the wheels. “What a coward!” says one woman. “He wouldn’t even stay to argue with us!”

What happened inside the Queen’s Head, I ask one of the breastfeeding mothers moments later. “He got an eyeful of our boobs and then got embarrassed,” says Becky, holding her 16-month-old daughter Iris. Mike Kear, a freelance photographer who took pictures of Farage in the Queen’s Head, said he felt very threatened by the aggressiveness of Farage and his aides. “He kept saying, ‘Where are you from?’ So I said, ‘Where are you from?’”

Later that afternoon, some of the activists meet back at the Richmal Crompton for a debriefing. By then, though, Ukip has spun the story in a way they couldn’t anticipate. Farage has castigated the activists as “scum” who have driven him from a quiet family lunch and led to him losing touch with his children for a few fraught moments. Sky News, the Guardian, the Mirror and ITV have gone with the “scum” story. Message boards on mainstream media sites (the Mail Online, for example), seethe with middle England raging against counter-cultural protesters. Suddenly Farage looks like the victim, and the activists – whose cabaret was aimed at drawing attention to how they feel victimised by Ukip’s attacks on their communities – look like aggressors.

Next, I start receiving hostile texts from activists: the story in the Guardian is presumed to have been written by me, the only journalist on the scene. It wasn’t. “Back-stabbing Red Tory rag,” comes one text. “Get tae fuck,” comes another. When I text back that I wasn’t the author, I get some apologies. “My love for fellow disabled people and all of us under the jackboot of austerity is so strong I won’t tolerate falsehood or defamation of our community,” says one.

Fair enough. But looking back on the day two things strike me. One is Farage’s use of the word “scum”, which recalls French president Nicolas Sarkozy’s similarly vile hate speech in describing Parisian rioters as “canaille”. The people I spent the day with aren’t scum; rather, they represent what I want my country to be in 2015 – diverse, creative, spirited, cheerful, understanding. But there is a countervailing point to be made. Bouncing on politicians’ bonnets and thereby managing to make them appear as victims? Not just wrong, but tactically jejune. “From what I can tell we pretty decisively lost the ‘battle of the story’ in the media,” Andrew Boyd emails me on Monday morning.

He’s right, and there is a lesson in that. Before Glass and the rest of his diverse cabaret descend (and let’s hope they will) on David Cameron’s local, they should think through what was good and bad about that strange and – but for 90 seconds – lovely Sunday in Kent, not least so they don’t get outmanoeuvred again.