Most critics lean positive on the opening episodes, and the praise clusters in two places: the bomb disposal set pieces, which several reviews find properly stressful, and Vicky McClure, whose composed, tough-but-sensitive lead is credited with holding the show together even where the writing does not. Reviews of the premiere call it tense, slick and diverting, and more than one admits it is preposterous while conceding it is good fun. The Line of Duty connection is mentioned throughout, usually as a promise the series is expected to keep.
The reservations gather around the script and the ending. Early reviews already note predictability and a slow first half. The two finale reviews, from The i Paper and The Telegraph, are the coolest, finding the resolution rushed and implausible, with The Telegraph judging that the series lapses into self-parody after a strong start. The spread is wide, from warm to disappointed, and it tracks closely with when each review was written.