Down-at-heel London-based private detective Tommy (Riz Ahmed) is investigating the disappearance of a Russian sex worker when he stumbles across a corpse. The body’s identity pulls him into a shadowy web of intrigue tangentially related to a tragedy that took place during his teenage years, and to which the narrative keeps flashing back. If the essential elements of “City of Tiny Lights” seem familiar, it’s because they are. Yet director Pete Travis’s film is distinguished by some transposition of noir tropes into cultural spaces not traditionally associated with the genre — from the London bar scene to a mosque — that keeps things from feeling too déjà vu.

On paper, this downbeat thriller is a surefire winner. Riz Ahmed, one of the best and fastest-rising of the current crop of young British actors (and probably about to go properly stellar in “Star Wars: Rogue One”) plays a PI written in the Sam Spade vein: cynical, but with a heart that yearns for the girl that got away, played as an adult by erstwhile pop star and “Doctor Who” alum Billie Piper.

London too is a city that can serve neo-noir well: It has no shortage of atmospheric yet seedy locations, dripping with hard-bitten history, and steeped in some of the worst dog-eat-dog instincts of contemporary free-market capitalism. A plot that intertwines adolescent sexual tensions forged years ago with latter-day corruption in the property market has the makings of a potential Brit-flick reimagining of “Chinatown.” Travis, meanwhile, is credited with helming the muscular, thrilling dystopian noir of 2013’s underrated “Dredd”; even if Alex Garland’s publicly acknowledged “showrunner” role on that film makes it unclear which creative decisions were whose, “Dredd” ostensibly marks Travis as a good fit for both the genre and sentiment of “City of Tiny Lights.”

And yet. And yet. Though pleasant enough to watch, there’s something not fully realized about the final product here. Despite the best efforts of the moody score and grade (often pushed in club scenes to the kind of lurid neons favoured by Nicolas Winding Refn), the pacing feels indulgent. The storytelling is too often allowed to meander, with an apparent reluctance to kill those darlings: Several sequences don’t serve much purpose beyond building ambience, even where it might have better served the film overall to forego some scenery in favor of tension. If the twists and turns of, say, Fritz Lang “The Big Heat” could be wrapped up in 90 minutes with atmosphere to spare, it hopefully doesn’t feel too ungenerous to suggest that another pass in the edit suite on “City Of Tiny Lights” could have profitably pared things down. It doesn’t help that the villain is pretty much hiding in plain sight the whole time; the audience is left wanting our man to get there a bit quicker.

Ahmed is asked to shoulder pretty much the whole pull of the narrative: a big ask given the limitations of his character. One of Tommy’s most memorable personality traits is his affection for a particular brand of whiskey — mentioned so often it stirs memories of the arch product-placement satire in “Wayne’s World.”

Ahmed is capable of playing understated charm and great vulnerability, as we’ve seen in a range of roles from a would-be terrorist in the daring Jihadi comedy “Four Lions” to the humane assistant to Jake Gyllenhaal’s bug-eyed paparazzo in “Nightcrawler.” Tommy doesn’t provide him with as much to get his teeth into, though there are certainly glimpses of what could have been, given a slightly more robust execution of the picture’s promising ingredients. Adapting his own novel, screenwriter Patrick Neate throws in stray bits of hardboiled voiceover, but it’s a device absent for so much of the film that it’s a bit of a surprise when it pops back up again. A committed decision either to excise the voiceover entirely or lean into it as a full-throated throwback to Bogart-era gumshoe pics might have helped.

Slotting comfortably into a modest family of London neo-noirs whose recent additions include Gerard Johnson’s corrupt cop yarn “Hyena” and offbeat Jason Statham vehicle “Redemption,” “City of Tiny Lights” should find favor with similar audiences, but forecasting a crossover to more mainstream success would feel optimistic. Notable as an early lead for its likely soon-to-be-A-list star, distribution would be wise to capitalize on “Rogue One” hype when dating what will likely be a modest roll-out.

Film Review: ‘City of Tiny Lights’

Reviewed online, London, Sept. 11, 2016. (In Toronto Film Festival — Special Presentations.) Running time: 109 MIN.

  • Production: (U.K.) An Icon release (in U.K.) of a BBC Films, NDF, Sixteen Films, BFI production. (International sales: Protagonist Pictures, London.) Produced by Ado Yoshizaki Cassuto, Rebecca O’Brien. Executive producers, Michiyo Yoshizaki, Marc Samuelson, Charles Auty, Peter Hampden, Norman Merry, Fumio Nagase, Christine Langan, Joe Oppenheimer, Natascha Wharton.
  • Crew: Directed by Pete Travis. Screenplay, Patrick Neate, adapted from his novel. Camera (color), Felix Wiedemann; editor, David Charap.
  • With: Riz Ahmed, Cush Jumbo, James Floyd, Billie Piper, Roshan Seth, Reiss Kershi-Hussain, Hannah Rae, Antonio Aakeel, George Sargeant, Mohammad Ali Amiri, Alexander Siddig, Vincent Regan, Barry Aird.