Something strange is happening at Channel 5. A broadcaster that has long been derided as trashy and derivative, trailing the main UK TV networks on both quality and viewing figures, is starting to remake its reputation.

The channel won its first Bafta in May and was named the best UK broadcaster by a panel of senior television executives at the Edinburgh TV Awards in August. At the same festival, the channel’s decision to stop airing Big Brother (its most popular show, acquired from Channel 4 in 2011) was confirmed.

In September, it began screening shows featuring prestigious names, such as Michael Palin and Jeremy Vine, and announced distinctive original dramas. While stations such as Channel 4 and BBC Two lose viewers, Channel 5 is gaining them. What has changed?

Channel 5 was launched in 1997 with the ambition of capturing a mass youth audience. Its pre-launch campaign included the Spice Girls performing a new song, “Power of Five” (an adapted cover of Manfred Mann’s “5-4-3-2-1”), with lyrics boasting of “a brand new station” for “a new generation”.

Presenters Tim Vine and Julia Bradbury described Channel 5 as a “modern alternative to old-style TV channels that expect you to fit in with their schedule”, emphasising that the network would broadcast a film every weeknight at 9pm, as well as “documentaries you’ll actually enjoy watching”, uproarious comedy, and relatable dramas – all for “free” and at regular times. But Channel 5’s original raison d’être was swiftly eroded by the arrival of cable television and online streaming.

Having struggled to compete with other networks over the past decade, Channel 5 has earned a reputation for lowest-common-denominator entertainment programming. Beyond Big Brother, its trademark shows have included poverty and prosperity porn (Rich House, Poor House and Can’t Pay? We’ll Take It Away!), exploitative obesity safaris (My Gastric Band Ruined My Life, Saving Britain’s 70 Stone Man), salacious true crime retellings (Born To Kill?, Murder Files) and industry tell-alls (Eddie Stobart: Trucks & Trailers, Nandos: A Peri-Peri Big Success). These shows were supplemented by imported Australian soaps (Home and Away, Neighbours) and US programmes (CSI and Law & Order, hospital dramas Grey’s Anatomy and House, and revivals of The X Files and Will & Grace).

But this year, the channel has moved beyond this hackneyed line-up. Michael Palin’s recent travelogue series on North Korea was the most-watched show in its time slot (with 2.5 million viewers) and, with the exception of Big Brother, the channel's most popular programme in four years.

“Channel 5 is experiencing a solid 2018 with both viewers and critics and is set for an interesting period of creative renewal now that Big Brother has finally been cancelled,” Max Goldbart, a reporter for industry magazine Broadcast told me. “Five years ago, a Michael Palin North Korea travelogue would have seemed textbook Channel 4 or BBC2, and the idea it might end up on Channel 5 would be laughable,” he says.

Radio Times commissioning editor Kasia Delgado cited Palin’s documentary as the moment she began to take the broadcaster more seriously. “It was Channel 5 saying, ‘Hello, we’re here, remember us?’ You’d be surprised to find out it was a Channel 5 show,” she told me. “That they have let Big Brother go is a big part of what could be the channel’s renaissance, because they have freed up money for other programming – like drama.”

Indeed, the cancellation of Big Brother has provided £20m to invest in original programming. To this end, Channel 5 has commissioned Cold Call, a psychological thriller starring Sally Lindsay, and Clink, a drama set in a female prison. It has also acquired the UK rights to Blood, an Irish thriller “exploring family, memory, and the impact the past can have on the present”.

Ben Frow, who as director of programming since 2013 has overseen the channel’s recalibration, told me he was “changing perceptions of Channel 5 and encouraging our audiences to re-evaluate what we do”. He credits more original programming with the channel’s improving reputation, alongside “a more diverse schedule and the introduction of new genres, from issue-led documentaries to accessible history programmes, natural history to talent-led travelogues.”

“The change has been driven in no small part by Ben Frow,” Goldbart told me. “He may not be the most popular, but is highly respected and stands far more intellectually tall than previous Channel 5 operators.”

The channel’s renaissance contrasts with the struggles of BBC Two and Channel 4. Goldbart explained: “Channel 4 is failing to get the big numbers under new director of programmes Ian Katz [Newsnight’s former editor], while BBC Two’s budget is at a five-year low.” Delgado noted that Channel 5 was now capable of surpassing Channel 4’s viewer ratings.

The notion of Channel 5 as a credible competitor to the BBC and Channel 4 would once have appeared absurd. But the insurgent network is raising its sights. “In 2019 we will undergo the next phase of creative renewal,” Frow told me. The channel would, he vowed, “continue to surprise viewers and TV critics alike”.