The trailer for David Mackenzie’s new thriller gave distinct “David Koepp scripted, Steven Soderbergh vibes,” and rightly or wrongly, that benchmark was in my mind when watching the actual film. Those smart, witty thrillers of Soderbergh’s late career resurgence like Kimi, or Black Bag all feel like Relay’s older, slightly distant relatives. While Black Bag was cannily described by someone much more articulate than me as “Tinker Tailor Soldier Spy meets Who’s Afraid Of Virginia Woolf,” Relay feels more like Drive meets Michael Clayton, and for the most part it delivers on this promise.

Riz Ahmed stars as Ash, a fixer for corporate whistleblowers looking to safeguard themselves after uncovering corruption. In a wordless opening sequence, we see him shadowing a client (Our Flag Means Death’s Matthew Maher) through a handover of incriminating documents. It’s an economical, elegant demonstration of his quiet efficiendy and competence; an understated echo of the opening car chase from Drive. Ash’s carefully cultivated anonymity is threatened when he takes on a new client Sarah (Lily James) a scientist in possession of damning documents from a bioengineering firm, hotly pursued by a sinister security agency (led by a grimly determined Sam Worthington).

The film’s most striking conceit lies in how Ash communicates with his clients. He uses a relay service designed for the hearing-impaired, as a way to retain his anonymity, remaining unseen and unheard. His clients never hear his real voice, and the confidentiality of the service makes him impossible to trace. This also means that, much like the taciturn protagonists of Drive, Le Samourai, Thief and The Driver, we are nearly forty minutes in before we hear our protagonist speak.

The effortlessly charismatic Ahmed seems to relish the challenge of a largely non-verbal role. Following his powerful dramatic turns in indie hits like Sound Of Metal and Mogul Mowgli, you might think he’s slumming it taking the lead in an actioner like this, but he proves an inspired choice for the lead. He is an effortlessly engaging presence, with an intelligence that radiates from the screen elevating what could have been a rote genre archetype into something more human. He’s implacable, dispassionate and yet every conflicting emotion is writ large on his face.

Lily James is less successful, but then her role is a fairly thankless one. It sometimes feels like there’s a bit of a tug of war going on between Ahmed and James over exactly what kind of film they are in. Ahmed seems intent on making a sleek existential thriller, clearly reveling in the minutiae of the role, while James appears to be in a softer, less interesting film, one where she inexplicably finds herself developing feelings for Ash despite never heard his voice or seen him in person. How much you care about this potential romance will likely determine how successfully some of the late plot contrivances land – for me they just about worked, although the final scenes are more than a little anticlimactic.

Sam Worthington is better than he has any right to be as the corporate heavy, bringing a sardonic wit and weary menace that make him a decent foil for the more cerebral methods employed by Ash. Unfortunately though, he’s sidelined in the films final act, just when you think he would get his moment to shine. Even better is Strange Darling’s Willa Fitzgerald, who steals every scene as his mercurial flunky. She imbues her character with a sardonic, rebellious persona that really makes an impression and deserves far more screen time than she gets.

Relay is a straight-faced, simple thriller that works precisely because of how straight the drama is played. There’s no detached irony or winking at the camera, it’s simply a slick, tautly paced thriller that channels the paranoia of 1970s classics like Three Days Of The Condor and The Parallax View, thought Relay never quite matches the fatalism of those films. What the film does really well is establish Ash’s process, his technique, and professionalism. Unlike something like The Killer, where the apparently meticulous hitman sees his carefully planned hit fall apart immediately, Ash is very good at his job, and Mackenzie wisely allows the film room to breathe in these scenes, recalling the technical scenes of safe-cracking in Thief. There are also a handful of highly suspenseful, off-kilter set-pieces that are genuinely impressive, including a nail-biting sequence at the opera that feels uncomfortably reminiscent of Blow Out, and a particularly great one in an airport that consciously echoes the “we just got made” scene from Heat.

It’s a shame that the film grows more conventional as it races toward its finale. The precision and restraint of the first hour give way to something broader and less distinctive . It remains gripping, but the conclusion feels rushed, with several characters’ fates left frustratingly ambiguous. It never really gets as nasty as I wanted it to, and compared to Mackenzie’s previous work, especially Hell Or High Water and the underrated Starred Up, it all ends up feeling a little toothless.

Maybe I’m damning with faint praise, but Relay is a quietly assured little thriller. It doesn’t break the mould but it doesn’t try to, and as the final playful capper demonstrates, it never takes itself all that seriously. Ahmed is an engaging lead, the assured direction means that it’s never boring, and though the ending is disappointing, it’s not enough to derail a fun ride.

Relay is in cinemas in the UK and Ireland now