‘It was about half one in the morning,” says Peter Knowles, recalling the peak of his crazy year as the controller of BBC Parliament, namely the night of the failed prorogation. “Black Rod showed up and Mr Speaker stayed in his chair. It was poisonous and marked a low point between the two sides. The speaker was sticking his neck out, saying this prorogation wasn’t lawful – and it didn’t look like he’d given Black Rod any warning. This was a very vivid drama playing out in the middle of the night. In terms of what I’ll remember from the year, it’ll be hard to beat that.”

Anyone pondering the state of British politics in 2019 may have reflected that every crisis is an opportunity in disguise. This year saw a brisk trade in ringtones of John Bercow, the former Speaker, bellowing “Order!” The spider brooch worn by the supreme court president Lady Hale as she shattered Boris Johnson’s dreams kickstarted a trend for animal-shaped accessories. And BBC Parliament – hitherto the forbidding, small-screen equivalent of the headmaster’s study – became our newest TV obsession.

It wasn’t long ago that Knowles struggled even to access his channel’s viewing figures “because people assumed it was next to nothing”. But in September, as Britain’s political skip fire blazed out of control, the channel hit 4 million viewers over the month and 2.6 million in the week of the failed prorogation. BBC Parliament has been the runaway BBC success story of 2019; the only channel with soaring numbers.

How does it feel when a bunch of politicos find themselves at the helm of a TV smash? “I absolutely love it,” grins Knowles. “We’re a tiny team: there’s only 12 of us. So the delight we get from people comparing the channel to season finales is huge.” Visiting BBC Parliament in November, it was hard not to share that delight. Based in a well-appointed eyrie a stone’s throw from the Houses of Parliament, the office buzzed with purpose. “It’s fraught,” said Knowles. “We’ve been able to enjoy our increasing audience, but there’s a sense of a lot being at stake, so there’s anxiety. And every day there’s protesters, singing, screaming, shouting, jostling – overlaid with the heavy anti-terrorism security.”

With the election calling a temporary halt to the channel’s most pressing business, a certain amount of stock-taking was in order. “When I arrived here, the content was actually quite weak,” says Knowles. “Tony Blair had an overwhelming majority; it was before the Iraq war. The Speaker did not call urgent questions. Parliament wasn’t that important.” At what point did it become clear something extraordinary was afoot? “If you have a hung parliament [as the UK did from 2017], you’re in business,” he says. “But there was a falling away of interest until the Brexit deal was written and the meaningful votes started in January. At that point, it really kicked off.”

The channel’s livestream became a high-stakes hit in uncertain times. But, besides viewers’ horror at what the future might hold, what made this drama so gripping? Parliament certainly has a dusty period-drama feel, with its archaic rituals and MPs draped on green or red leather benches. But proceedings can feel hyper-modern, too. Watching Chris Pincher evade questions on the non-publication of the report into Russian interference in the EU referendum felt similar to seeing a suspect squirm during an interrogation scene on Line of Duty.

Watching BBC Parliament also has a realness that recalls the 24-hour live feeds from the early days of reality TV. “It’s the authenticity and rawness that really appeals,” says Knowles. He is aware, too, of his role in helping people make sense of the mayhem. He speaks of attempting to demystify, using captions and documentaries. “I think there’s a willingness to engage with and spend substantial chunks of time with something you’d never usually have bothered with,” he says. “A lot of people are becoming more engaged and civic-minded.”

Of course, this high drama had a postscript; one that offers finality for the issues that created its startling success. Thanks to the large majority gained by the Conservatives on 12 December, this unlikely sleeper hit will struggle to maintain its tension. Speaking after the election, Knowles says: “It’s a very different world we emerge into. Knife-edge votes and the drama that came with them may happen again at some point. But not in the next five years.”

The channel is preparing to accept a different level of prominence. “It’s never been ratings-driven,” says Knowles. “So it came as a delight when we hit the big time. But I’d be kidding myself if I thought we could hit 4 million in the near-future.”

Will he look back fondly on those thrilling September days when the country was transfixed? “I have mixed feelings,” he says. “It had become exhausting for everyone. For a parliamentary channel, there’s nothing more exciting than covering a vote and not knowing who’s going to win. But there was possibly a limit to how much excitement the audience could take.”