'Line of Duty' Season 5: TV Review

Yes to all great cop shows.

With the first four addictive seasons on both Acorn and Hulu, Jed Mercurio's pulsating police drama returns after enthralling Britain for its fifth season.

Chances are that if you're already a fan of the hit British police drama Line of Duty and you're from this side of the pond, you've been counting down the days to the start of season five. The show has already aired in the U.K., pulling in a huge 13.2 million viewers for the first episode and becoming the highest-rated drama of the year so far, averaging 10.6 million viewers as, like the previous four seasons, it rivets the nation.

If you don't know anything about Line of Duty, here's the thing — it still holds up as a compelling story, even if you're missing the myriad call-back references from the first four seasons that creator and writer Jed Mercurio (Bodyguard) is known for, as his insanely twisted plots tear through story and drop red herrings galore.

In fact, there's a decent chance that many American viewers discovered (and probably loved) Mercurio's wild style when they watched Bodyguard on Netflix, which careened madly, addictively and, yes, sometimes implausibly, through the miniseries' run.

But in Britain, Mercurio is still best known and appreciated for Line of Duty, which returns for its fifth season on Acorn, the niche streamer of international (but largely British) fare (Acorn also has the first four seasons, as does Hulu, though only Acorn will have the fifth season when it premieres May 13).

Line of Duty focuses on the Anti-Corruption unit, AC-12, which investigates police corruption and over the course of four seasons has found plenty of it, often ending each what-the-hell, gasp-filled season with violent ends. But what has been intriguing on top of Mercurio's caffeinated plotting is that each season relates in some ways to the one before it, or sometimes multiple seasons together (though, as stated, new viewers don't need to know that to enjoy season five).

The series revolves primarily around Detective Inspector Kate Fleming (Vicky McClure, Broadchurch, This Is England) and Detective Sergeant Steve Arnott (Martin Compston) and their boss, Superintendent Ted Hastings (Adrian Dunbar), who started ferreting out corruption in 2012, getting immediately likened to a number of American cop series, including The Wire — though its closest cousin is probably The Shield, which puts it in strong company. 

It's probably fair to say that Line of Duty was slightly more grounded in the first season and its fame led Mercurio to raise the stakes — and since he's quite adept at that, Line of Duty quickly became an ever-more suspicious affair, where it seemed in short order that Birmingham in England was rife with more corruption than New York, Baltimore or L.A.'s Ramparts could keep pace with. And if, in the later seasons — where fans would argue the shocking turns have become more impressively baroque — there has also been more suspension of disbelief in the execution of Mercurio's magic, it hasn't dulled the audience's enthusiasm (or, for that matter, the critical praise). And Mercurio often has his most now-wait-just-a-minute moments given more slack than dubious examining precisely because he's driving the car at high speeds and no brakes. (You could argue that this generosity in just going with it has also blessed Luther.) 

If you know that going in it helps, if for nothing else once you cut Line of Duty some plausibility slack, the series can then be absorbed for its massively entertaining elements. It has become known for inserting a number of compelling British actors into key seasonal roles, like Lennie James (The Walking Dead), Keeley Hawes (Bodyguard, The Durrells in Corfu), Thandie Newton (Westworld) and this season Stephen Graham (Boardwalk Empire, This Is England), letting them drive the series without stealing any thunder from the regular cast. It's a nice conceit, even if every new face conjures up that "oh, this will end badly" vibe. It's a testament to Mercurio that just when you think, "Well, this person is clearly guilty, as all the evidence suggests," he's got multiple switchbacks and loopholes to play with.

In season five, Graham's undercover cop is in way too deep and too frequently crosses the bright moral line, which is also a trademark of Line of Duty— as a series it always questions what is worse, and what is gained or lost in the pursuit of justice in the gray margins.

Given that both Acorn and Hulu can get you started and Acorn can catch you up to the present — yes, a sixth season is also a go — there's probably no reason for viewers to leave this undiscovered. And if you are already joining our cousins in Britain voraciously devouring each offering of Line of Duty, then your days of counting down are almost over. On Monday, Line of Duty really leans into the four seasons that came before it and more connections than ever will be made. If you're thinking those connections are corrupt, yes, that's a good start. 

Cast: Stephen Graham, Vicky McClure, Martin Compston, Adrian Dunbar, Maya Sondhi, Polly Walker, Taj Atwal

Created and written by: Jed Mercurio

Directed by: John Strickland, Sue Tully

Premieres May 13 on Acorn