ITV thriller series Betrayal starring Endeavour and Vigil star Shaun Evans and Atonement‘s Romola Garai has officially started filming.

Branded as a “gripping espionage thriller”, the series digs into the spy world of MI5, following Evans’ character John Hughes as his professional and personal lives unravel.

Set for a 2026 release, the series hails from A Very Royal Scandal director Julian Jarrold and screenwriter David Eldridge, and is currently in production in Manchester and Liverpool.

As per the Betrayal logline, mid-career MI5 officer John Hughes is grappling with a rapidly changing security landscape and his own personal demons.

John’s clandestine encounter with British-Iranian informant Ehsan ends in bloodshed, resulting in the agent to come under scrutiny from superiors, including Simone Grant (Nikki Amuka-Bird).

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The incident puts a strain on his marriage to GP Claire (Garai), with their relationship suffering further pressure with the arrival of Mehreen Askari-Evans (Zahra Ahmadi), an ambitious operative who’s been transferred from MI6.

The cast for the series is rounded out by The Outlaws‘ Gamba Cole, His Dark Materials‘ Omid Djalili, Grantchester star Matthew Tennyson, Coronation Street star Hayley Tamaddon, and House of the Dragon‘s Anthony Flanagan.

Paddy Rowan, Waj Ali, Karim Kadjar, Emma Cunniffe, Georgina Rylance, Ben Lambert, Julia Watson and Julian Wadham also star, with newcomers Elham Karimpour, Aidan Rivers, Corin Silva and Eliza Agrosoaie also joining the cast.

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When the series was announced last September, Evans said he was “delighted” to return to the ITV for the “exceptionally well-written and timely project”.

“It’s a great privilege to reunite with David Eldridge and bring to life his insightful take on the world of espionage,” Evans said.

“And it is of course a joy to be collaborating once again with the first-rate team at Mammoth Screen. I look forward to sharing it with ITV audiences soon.”

Betrayal will premiere on ITV1, STV, ITVX, and STV Player in 2026.