Secret State, Channel 4

The political thriller may be alive and well but in recent years it has been spending time abroad. Elements of government conspiracy are intense flavourings of, for example, The Killing and Homeland, while back in Blighty there has been little to trouble the scorers since Paul Abbott’s State of Play nearly a decade ago. Why? British drama has been too busy scoffing at Blair and Brown, Cameron and Clegg to worry itself with shady Whitehall cover-ups.

Chris Mullin’s 1982 what-if page-turner became a landmark BBC drama by Alan Plater six years later, and is now the source for Channel 4’s new four-part drama. Quite what “inspired by the novel” actually means is hard to pin down. The plot supplied by Robert Jones (last seen less compellingly poring over the story of John and Yoko) feels at this point like its own thing. The overlap is less in events than atmosphere and archetypes. Once more we find a good man at the heart of a rotten system, in this case Deputy Prime Minister Tom Dawkins (the surname is perhaps not a coincidence), who is surrounded by a grim gallery of politicians, civil servants, security apparatchiks, all apparently in the service of big bad money.

The poker face Byrne deployed in In Treatment serve him superbly here

Damocles is dangling a couple of swords over Dawkins. We first meet him inspecting a scene of urban devastation. An explosion at a plant in the North-East has killed 19 and injured 94, not all of them workers: the glove we see Dawkins pick up from the rubble contains tiny fingers. The other coming threat seems more everyday. At a time of economic woe, Dawkins’s party of government is shortly to face the wrath of the electorate.

The one politician whose prospects of being returned to No 10 slump to zero is the PM (Tobias Menzies). He jets over to agree compensation with the plant’s US owners Petrofex, only for his plane to fall out of the sky on the way back. This sets off an unseemly battle for the succession, led by Rupert Graves’ weaselly pinstriped squirearch Felix Durrell and Sylvestre Le Touzel’s jackbooted scarecrow Ros Yelland. Le Touzel (pictured below right with Byrne and Graves) is a particular hoot, and clearly the cap fits because she played someone extremely similar in the final series of The Thick of It.

Meanwhile, behind the scenes Charles Dance’s saturnine chief whip is yanking on all sorts of strings, and Lia Williams’ security chief, who seems to have eyes in the back of her head, is homing in on the evidence that the plane crash was the work of al-Qaeda, even if it conveniently extricates Petrofex from a verbal commitment to pay up. Other interests all with an ear to the ground are a campaigning journalist (Gina McKee), a young spook at GCHQ (Ruth Negga) and a boozy old pal of Dawkins from the security services (Douglas Hodge).

At the heart of this nexus, Dawkins has his own demons to fret over: a ruined marriage, and the haunting memory of a questionable record as an army captain in Bosnia. Although the conspiracy has so far yielded just the one extra corpse (a pathologist who smelt a very toxic rat in the bodies of two of the blast victims), by the end of this first episode hints of Petrofex’s malfeasance were becoming ever more putrid, while Dawkins’s spine was slowly stiffening.

As an Irishman making his British television debut, Byrne may seem a left-field choice to play a UK politician. But the poker face and soft voice he deployed in In Treatment serve him superbly here, and he has been surrounded by character actors who can play the layers of Secret State consummately. There was even a little cameo for Chris Mullin as a padre loitering outside the PM’s funeral.

This first episode did exactly what any opening of a political thriller should: it took your lapels in a vicelike grip. It doesn’t look as if Secret State will let go until the last mystery has been unravelled. If it’s a happy ending you’re after, step away now.

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