Rooted in reality, Peter Kosminsky's new series The Undeclared War harbours warnings and an all-star cast, as Danielle de Wolfe discovers.

There's nothing quite like the prospect of a digital cold war to instigate the return of one of the nation's best-loved actors. Recent years have seen Simon Pegg become an increasingly prominent Hollywood presence.

After getting pally with Tom Cruise whilst playing protagonist Benji Dunn in the Mission Impossible franchise, all it seemingly took was a script five years in development, delving into the nuances of international cyber warfare, to lure him back from across the pond.

"Yes, please. I'd like to come home," whispers the 52-year-old actor, recreating his acceptance of Bafta Award-winning writer and director Peter Kosminsky's script. "It just felt like a no-brainer to me...I was extremely flattered to be sent the script, just because it's not the kind of role people assume that I would be interested in."

With the glory days of the Cornetto Trilogy apparently far behind him - an anthology of comedic films co-written with Last Night In Soho director Edgar Wright - his latest role as part of Kosminsky's new six-part thriller The Undeclared War stands as one of his grittiest to date.

It's a series that has already garnered the nation's (and Ofcom's) attention as part of a controversial, yet highly creative, marketing campaign. The bold stunt saw fake cyberattack warnings televised across all Channel 4 channels on the evening of June 10. Direct from a fictionalised GCHQ, the fake government message saw actor Adrian Lester (The Day After Tomorrow) deliver a speech as Prime Minister Andrew Makinde.

A REALISTIC THRILLER

Set in the year 2024, The Undeclared War is anything but an optimistic, post-pandemic watch. A premise which sees the UK engaged in cyber warfare with Russia, the unfurling events hold the potential to bring the nation to its knees.

"The reason I wanted to make this is the same reason I've always wanted to make stuff really," says Kosminsky. "If you discover there's something going on that you didn't know about - and I'm a reasonably well-read person, so if I don't know about it, I suppose there's a fairly safe assumption that a lot of people won't know about it - then it's my job to cast a light on it."

Delving into the bowels of GCHQ - the Government Communications Headquarters overseeing national intelligence and cyber security - we meet a team of analysts working tirelessly to ward off an unrelenting series of cyber attacks. What appears to be a run-of-the-mill stress test on the nation's infrastructure rapidly takes a dark turn, placing the team at the forefront of an international cyber war.

It's a scenario that doesn't require all that much imagination, given the current state of international relations. Unsettling in the extreme, it's a premise very much rooted in reality according to Wolf Hall and The Government Inspector director Kosminsky.

"I'm not saying this is the way things will turn out," says Kosminsky. "But I'm saying there's nothing in this show that either hasn't happened, or is not being sort of 'war gamed' by the people here and in other countries who try to prepare for this kind of thing."

Labelling the series a "hot war going on in cyber space", the creator says he was "really shocked" by the "fragility" of our heavily internet dependent society.

"I call it a cautionary tale because I think that if we're not careful, this hot war will escalate to the point where it threatens our civilisation. I think it's as serious as that," adds Kosminsky of the very real premise.

Noting the best way to tell such a complex tale is through the eyes of a "relatively ordinary" outsider, The Undeclared War sees a 21-year-old intern with little understanding of the world she is about to enter at the forefront of events.

A tale which also explores the contrasting opinions of civil servants and elected politicians - with the latter having "a very different agenda" according to the writer - the drama offers a unique perspective on the running of our nation.

"A populist government is imagined here in this case, which is trying to please a constituent base - and obviously, we're familiar with that phenomenon elsewhere," says Kosminsky. "There may be a very real and apparent conflict between what might, to some of these civil servants, seem to be the right thing to do, and what those populist politicians might feel political necessity dictates."

THE CAST

The Undeclared War sees emerging star Hannah Khalique-Brown take on the role of intern Saara Parvin. A fresh-faced cyber protege, the role saw the actress learn two programming languages and get to grips with basic coding in preparation for the role.

Explaining the show's unique "Code World" scenes - a "surreal landscape" which allows viewers to see a physical manifestation of everything that's going on in Saara's mind - it's a series which transfers thinking and the inner workings of the brain on to our screens.

"It serves a really useful purpose," notes Khalique-Brown. "One, in that it can show the audience and the ordinary layperson who doesn't know how to code the structure and the way that it works - calling up tools like a tool belt. And it also serves to help me find out how her brain works because Saara is a really incredible, extraordinary, astonishingly talented coder. She does think differently - she thinks 10 steps ahead of anyone else."

A series which also stars This Is Going To Hurt's Alex Jennings, viewers will likely spot a guest appearance from Academy Award-winning actor Sir Mark Rylance. Joined by Lester as Makinde - the son of a Nigerian diplomat, an Eton graduate, and a recent political leader - the show's backdrop makes it an undeniably relatable watch.

"In our story he ousted Boris Johnson and became the surprise leader of the Conservative Party," says Lester, 53. "So he's the Prime Minister, but not elected by the public."

Also starring Maisie Richardson-Sellers as Kathy Freeman, a cyber analyst who comes from the NSA - the American counterpart to GCHQ - the show sees Kathy and Saara connect as otherwise lone female wolves in the department. Guided by Shaun Of the Dead's Pegg as Danny Patrick, chief of operations at GCHQ, his character is described as a "den mother" by the actor.

"It's really enjoyable to play a character who's so far from the sort of thing I'm known for playing," says Pegg, noting it won't be long before he "gets back to playing idiots".

"As an actor, that's all you can hope for really, to be given challenges. And this was a glorious, glorious challenge."

The Undeclared War, Channel 4 on Thursday, 9pm.