The Undeclared War Episode 4 (Channel 4 Thursday 21 July 2022)

In the fourth episode, following an exchange with a Russian whistleblower, Saara is in a difficult position, as her boss Danny (Pegg), GCHQ Head of Operations, considers that the interaction could just as easily be a deliberately engineered seeding of misinformation. Meanwhile, Marina (Tinatin Dalakishvili) leaves Glavset to start work at Russia Global News, based in London.

Information is leaked, which puts a friend of Saara’s in grave danger, and her relationship with Kathy (Richardson-Sellers) becomes more complicated. Looking for an ally outside the system, Saara visits elderly analyst and iconoclast John Yeabsley (Rylance) at his house, where he provides an unexpected perspective.

Cyber thriller from BAFTA-winning creator Peter Kosminsky that lifts the veil on the most urgent battle of our time. Set in 2024, The Undeclared War tracks a leading team of analysts buried in the heart of GCHQ, secretly working to ward off a series of cyber-attacks on the UK in the run-up to a general election. When a routine stress test of internet infrastructure goes awry, 21-year-old GCHQ intern Saara Parvin (Hannah Khalique-Brown) suddenly finds herself operating on the invisible frontier of high-stakes cyber warfare.

In a thrilling cat-and-mouse game, Saara and the team at GCHQ must try to stay one step ahead and anticipate their opponents’ every hidden move. The clock is ticking as a battle with high stakes and unpredictable enemies takes place entirely online, with very real consequences. But how do you win a war that most of the public don’t know you’re fighting? Also starring Simon Pegg, Maisie Richardson-Sellers, Adrian Lester, Alex Jennings, Mark Rylance and Kerry Godliman.

Writer: Declan Lawn; Dir: Peter Kosminsky; Exec Prods: Peter Kosminsky, Colin Callender, Noëlette Buckley; Prod: Robert Jones; Prod Cos: Playground, Stonehenge Films and Universal International Studios for Channel 4 and Peacock

Airdate: Thursday 21 July 2022 at 9.00pm on Channel 4.

Season 1 Episode 4