H suspects (assuming they've been in since series 1)
-Hastings. Looks guilty as hell, suspected in season 5 and somethings are still at a loose end- why he told Banks about corbett, why he got his laptop trashed (lets not believe it was because of porn!)
- Steve and Kate-both seem a bit young- they'd have been in their late 20s/early 30s in series 1, and given Hunter's involvement, it's likely H was an older person who recruited Hunter. The other "3 H's" weren't really the masterminds, just the key people in the police, none of whom weren't particularly that smart. Could have been passed on, but seems a bit of a crappy ending.
-Nigel Morton- is he Keyser Soze?! He was happy to go along with Dot suggesting someone else was the cady in series 2, he was tipping journalists (to cause drama?!). He "retired" at the end, so he wouldn't have so much influence in the police, but could have set up enough of a network he doesn't need to be active.
- Buckells- already addressed.
-Osborne- too obvious. He's clearly corrupt and awful but he's basically a pantomime villain.
-PC Karen larkin and PC Simon Bannerjee-Larkin was one of the absolute worst. She went into Terry's flat and totally dismissed him-a quick check and she might have found Jackie Laverty in his freezer and saved Terry from a decade of not having ice cream or frozen chips. Was that on purpose?! She also told Bannerjee to stop chasing Ryan, was she making sure he was free or just rubbish? Ryan cited Bannerjee as an influence for him being on the force. We have no idea what happened on the estate after series 1.
- Keeley Pilkington- Ryan's mum was young and seen complaining in the police station and then later, lying on the sofa. Doesn't seem like she has the energy to be a criminal mastermind but the impression is given she let Ryan get into trouble and gang activity, was she a deadbeat parent or was it an act?! (highly unlikely but stranger things).
- DS Leah Janson- basically just there to stir things with Kate, which seems like a bit of a waste, she didn't really o anything. Could be misdirection, but highly improbable).
There's some other super minor characters- the old guy on the estate (double bluff?!), the lawyer or social worker who goes to the interview with Ryan, a few other police officers but that would be a bit of a cop out.