Did anyone else see this last night?
It was on BBC2, so that's a good-ish sign. Plausible, AFAIK, and well acted. The plot reminded me very much of the Scandic detective dramas and will get very convoluted over the following four episodes.
Basically, a high-flying, seemingly clean (black) DCI is ardently being hunted by an anti-corruption squad. In the meantime, he has covered up for his mistress' killing of an employee in a dodgy hit-and-run car accident and is trying to cover up his cover-up.
Recommended.