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Simon Pegg and Blue Lights favourite star in exclusive first look at return of cyber-thriller The Undeclared War

We return to GCHQ – but there seems to be a mole.

Hannah Khalique-Brown, Simon Pegg and Siân Brooke for The Undeclared War season 2.

Channel 4

Published: Monday, 29 June 2026 at 10:00 am

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With a first season that brilliantly captured the thriller-like near-future of Britain, The Undeclared War is returning to our screens for season 2 – and Radio Times has an exclusive first look at the exciting new trailer.

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The official trailer kicks off with Simon Pegg's (Mission Impossible) Danny Patrick plainly stating that they're faced with a "potentially nuclear piece of malware", and we then see new Foreign Secretary Richard Marston (Ed Stoppard) explain that it "constitutes the cyber equivalent of an armed attack on the United Kingdom".

Jason Tobin (A Thousand Blows) joins the cast for season 2, telling fellow new character Barbara (Siân Brooke) that everything they seem to be telling her people, they already seem to know immediately. Saara Parvin (Hannah Khalique-Brown) seems to come to a similar conclusion at GCHQ and Danny concludes that they have a mole.

Siân Brooke as GCHQ Analyst Barbara Patrick in The Undeclared War, looking in a mirror

GCHQ Analyst Barbara Patrick (Siân Brooke) Channel 4

Danny Sapani (Black Panther) joins the season 2 cast as Charlie Francis, GCHQ’s Head of Security and Danny’s childhood friend. But when he's faced with knowing who the allegation has been made about, he underlines the severity of the accusation, especially as it seems that it's being levied at a "senior and widely respected colleague". But who is it?

It's safe to say that the tension seems to be at an all time high and with a montage of scenes showing the team coming slightly undone, we'll have to wait and see just who could be at the centre of such deceit.

You can watch the trailer for yourself below.

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Of course, as the trailer shows, there are quite a few new characters joining the fold this time around. Blue Lights star Brooke joins the cast as Barbara Patrick, Danny’s wife, ex-MI6 and now an analyst at GCHQ.

Chloe Pirrie (Black Mirror) also joins the cast in a new role as Lt Colonel Roz Cavendish, seconded by Marston to GCHQ in the newly created role of Director of Rapid Response, a move which Danny interprets as a threat to his authority.

The synopsis for season 2 reads: "Set in 2024, The Undeclared War returns with a fresh wave of tension and drama as the elite Malware Department at GCHQ grapples with the aftermath of a devastating Russian cyber-attack. Just when it seems the UK has gained the upper hand, Danny and the team uncover a far more dangerous threat."

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The Undeclared War season 2 will air on Channel 4, while season 1 is available to stream now.

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Authors

Black and white cut-out portrait headshot of Morgan Cormack, smiling against a lime green background

Morgan CormackDrama Writer

Morgan Cormack is a Drama Writer for Radio Times, covering everything drama-related on TV and streaming. She previously worked at Stylist as an Entertainment Writer. Alongside her past work in content marketing and as a freelancer, she possesses a BA in English Literature.

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