I feel a little sorry for Better (BBC One). It’s a police show set in West Yorkshire arriving hot on the heels of Happy Valley, the best police show set in West Yorkshire ever to have blessed our screens. It’s a bent copper show coming slightly cooler on the heels of The Responder, also a bent copper show and one of last year’s best dramas. Through no fault of its own, it is destined to suffer under the weight of comparison.

I Hate Suzie’s Leila Farzad stars as DI Lou Slack, a corrupt detective in Leeds who has spent the best part of two decades taking money from the local drug baron Col McHugh (a menacing Andrew Buchan). When her son, Owen, suffers a near-fatal illness, Lou’s conscience begins to swing into action, and she questions her place at the heart of Col’s business.

It is unfortunate that, in order to explain what the show is, the trailers and all the usual bumf around a new series have revealed that Lou is a detective. The first 10 minutes or so assumes that we don’t know this and builds tension by asking the audience why this professional-looking woman might ditch her husband on a night out in order to break into a crime scene and clean it up. As she picks over the pieces of an ad-hoc drugs factory to find a weapon inadvertently left behind, she discovers a man who has almost, but not quite, bled to death. She ignores him and gets on with the job. As she is driving away, she is pulled over by police. It would be a heart-thumping moment, but the big reveal – that she can get away with it because she, too, is police – isn’t quite so effective when you know that to be the case.

Is Lou a cool and callous antihero, so ice cold that even soon-to-be-dead bodies don’t cause her moral compass to so much as flicker? Not quite, although I would like to see that version of Better. She loves being a detective, but loves the money she makes working with Col even more. She lives with her husband, Ceri, a builder, and Owen in a big suburban house with a spectrum of Farrow & Ball walls, and they have big fancy holidays and the police are just about the only public service not striking for better pay at the moment – because they are not allowed to. Yet nobody seems to wonder where this lifestyle is coming from.

The main thrust of the story is that after Owen’s brush with death, Lou grows a conscience and begins to wonder how she can extricate herself from Col and the dark side. “Please don’t die,” she begs, as she pleads for her son’s life at the hospital, “I’ll be better.” As the cosy quid pro quo between criminal and detective falls apart, Better starts to find its pace, and assert its own identity, though I did struggle to believe in Lou’s spectacular naivety. She seems repeatedly shocked by the reality of a massive drugs empire and what it takes to build and maintain it; for a hardened DI who has been on the job for such a long time, the idea that Col’s business would be conducted with gentlemanly handshakes and a spot of light cajoling seems absurd. Perhaps that is meant to suggest that Lou has been lying to herself, too.

Better’s strongest side, and most intriguing strand, is the relationship between Col and Lou, who have been in cahoots for such a long time that they are practically family, though the sort of family where someone has to have their phone confiscated and submit to a full body search before being invited into the house for a birthday party. The question of who is in charge here – the drug lord paying off the bent copper, or the bent copper who has kept the drug lord out of prison – is much more complicated than it first seems and when Lou refuses to stick to the rules, it turns into a gripping cat-and-mouse story. Farzad and Buchan are at their best when playing against each other, and each scene they share teases as to which way it will flip.

It’s a shame there is so much scene-setting in the first episode because once all that is out of the way, the drama is much less superficial than it first appeared to be. Information is drip-fed to give the story more depth, particularly when it comes to family ties, who is related to who, and who has lost what. It is very moreish and does get better.