Episode 5

Tony Gates is on the run, and the anti-corruption team is under real pressure to close the case once and for all. Fleming and Hastings go all out to catch him, while Arnott is forced into the kind of decisions that don't show up in the job description. The manhunt pulls everyone in, from the officers chasing leads to the ones keeping the office running. The streets are not big enough for a man with Gates's record, and he knows it. It went out in July 2012 as the finale of the first series, and it already knew exactly what the show wanted to be: a long, uncomfortable look at the people who carry the authority.

But the episode has the feel of a season finale that knows exactly what it owes its audience. It owes them a reckoning, and it delivers one. The pursuit of Gates brings together every thread of the series so far, and the conclusion lands hard. Along the way, Arnott has to work out where his loyalties actually lie, which turns out to be a more expensive question than he expected. Karen Larkin, Leah Janson and Ian Buckells all have their parts to play in the closing act, and none of them gets off lightly.

Jed Mercurio wrote it, Douglas Mackinnon directed. Lennie James gives Gates a last act that keeps the sympathy alive, while Vicky McClure's Fleming and Adrian Dunbar's Hastings push the hunt forward. Martin Compston's Arnott, Tomi May's Minkowicz, Gregory Piper's Pilkington, Nigel Boyle's Buckells, Claire Keelan's Janson, Fiona Boylan's Larkin and Kate Ashfield's Jools Gates fill out the final push, with Thomas O'Malley's IT technician in there too.

The weight of responsibility runs through the whole episode, and the ethical questions are not tidied away. Gates makes his choices and pays for them. The people chasing him make theirs and pay in other currencies. It is a taut, unhappy piece of television, and the better for it.