Britain is a conservative country, we are repeatedly told. So when Labour came into government, and Rachel Reeves became the UK’s first ever female chancellor of the exchequer, there were barriers to making change. The most striking, reports the satirist Rosie Holt, was to be found in the toilet of Reeves’ office in Westminster. “There was a urinal in No 11,” says Holt. “And Reeves told an interviewer, ‘I’m going to break glass ceilings and urinals.’ She was setting up getting rid of this urinal as a symbolic win. I thought that was funny and interesting.”

But things did not go according to plan. “She couldn’t get it removed, not only because the building was listed, but because the urinal was an object of historical significance. It had been pissed in by various chancellors – including Winston Churchill.” For Holt – standup, online character comic but also a lapsed theatre-maker – this story was irresistible. On last year’s fringe, she workshopped a new play making antic political farce out of Reeves’ battle with a historic pissoir. One year on, Churchill’s Urinal – written by and starring Holt with contributions from her ex-partner, the comedian Stewart Lee – has its London premiere.

“As a story, it encapsulates so many different things going on in the country right now,” says Holt, on a break from rehearsals. “The tribalism: people always get very extreme when it comes to Churchill. And also this idea of our first female chancellor, which surprisingly got very little fanfare. And what trying to forge that new path looks like.” I saw the work-in-progress of Churchill’s Urinal at the Shedinburgh venue last August, and can vouchsafe that Holt’s take on the tale gives us a concentrated hit of the partisanship, the sexism and the overblown absurdity of modern, culture wars Britain.

The show has evolved since, mind you. It began life as a play/standup hybrid, but has moved firmly into the theatre camp. That represents a homecoming for Holt, 40, who turned to comedy after training as an actor, “because I wanted creative control”. Her last theatre show was The Crown Dual, a hit two-hander parody of the Netflix royal family soap opera. Then came the pandemic, when Holt made her name with online sketches in character as a cannon-fodder Tory backbencher, doggedly defending the indefensible in fake TV interviews while the Johnson regime descended into squalor. She has since parlayed that act into several live shows.

Why not, then, stage the urinal story as satirical standup? “I remember when I talked to Stewart about it,” says Holt, “he said, ‘Oh, would you do it with the MP character?’ And I felt very strongly that I didn’t want to. What I wanted was a narrative structure and a sense of this woman getting completely overwhelmed by all these outside forces while trying to keep things together and keep a public face. I felt I could more effectively show that in a play than in standup.” And was it always going to be a play starring, er, Rosie Holt? “Yes it was. Isn’t that terrible?

“Putting myself in it was a very selfish no-brainer,” she says. “But that’s not why I wrote it. Otherwise I’d have just written a great theatre piece that can show my versatility. And I wouldn’t have written about politics, I’d have written something else entirely. I’m annoyed with myself that the first play idea I come up with is still based in the world of politics.”

Well, they do say write about what you know – and with Churchill’s Urinal Holt has created a play about not just the cut-and-thrust of Westminster life (her satirical subject these last five years) but about the hostile reception accorded to women in traditionally male worlds. “Especially during lockdown, my work was very public-facing,” she admits. “And you do sometimes get really extreme abuse, and sexualised abuse. Which as a man, you just don’t get. It’s a whole different level of trolling, which a lot of female MPs have to deal with as well.

“We’re now in this world where you go, ‘OK, it’s equal: a woman can become chancellor, a woman can do comedy.’ But there is still this underlying unease from some people that a woman isn’t quite good enough for those jobs. And that’s one of the things I’m addressing with this play.”

And will that play, about a bitterly divided country, elicit divided responses depending on its audience’s politics? “I thought,” responds Holt, “that you were going to ask: do you think this play is going to unite the people of Britain?” Chance would be a fine thing. “I do want to interrogate the fact that we are so split as a country,” she says, “and that we have a government that’s not giving any clear direction as to where this country should be going.” But more important, says Holt, is to ask: “What is a funny way of communicating that to the audience? I hope there will be moments of insight and poignancy. But I always wanted it to be funny throughout.”