Nightsleeper star breaks down major finale reveal: "For the longest time we didn't know"

The series depicts the so-called 'hackjack' of an overnight train from Glasgow to London, with several passengers inside being held to ransom as it speeds recklessly along the tracks.

Howell plays Tobi McKnight, part of a team at the National Cyber Security Centre (NCSC) who are frantically trying to put a stop to the nightmarish situation.

Little do they know that the perpetrator is in their ranks – read on for Howell's spoiler-filled reaction to Nightsleeper episode 6, which is available to stream now on BBC iPlayer.

Nightsleeper episode 6 reveals that Paul Peveril (David Threlfall), the eccentric ally to NCSC director Abby Aysgarth (Alexandra Roach), was in fact the malicious hacker they have been tracing the entire time.

"I really hope they don't see it coming," said Howell. "I really don't think they will. A lot of us in the control room didn't know for a while, and then we found out, and we were like, 'Oh, it's you!'

"We weren't playing it for a long time; for the longest time we didn't know, and that was really cool. And so hopefully that translates because we didn't know, so you shouldn't know."

Howell went on to say that he felt the twist was earned, with Paul's betrayal of his former team making sense due to his harsh treatment by the NCSC bosses – including Nicola Miller (Pamela Nomvete), who came under suspicion earlier in the show.

"He’s been ostracised, he's been sent out for trying to be this whistleblower about what's going on and what could happen and the state of things," continued Howell.

"When things are moving so fast and things are evolving so fast, and people who know the most are maybe being hindered by the government not realising the real level of the threat... what I saw was that frustration."

Howell added: "It’s the Chicken Little thing of 'the sky is falling, guys!' – and no one's listening... It was woven into that character and it's a really lovely climax."

In addition to Howell, Roach and Threlfall, Nightsleeper also stars Gangs of London alum Joe Cole as disgraced police officer Joe Roag, who manages the rising tensions aboard the hacked train itself.

Nightsleeper is available to stream on BBC iPlayer. Tune in on Sundays and Mondays at 9pm on BBC One.

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