Updated on 2 May: There is just one more episode of Line Of Duty season six left, and yet we have more questions than ever.

As such, the notes in our trusty notepads are getting a little… well, a little muddled. Is Kate Fleming (Vicky McClure) really the villain so many fans believe her to be? Is Jo Davidson (Kelly Macdonald) destined to be killed at the hands of a corrupt police officer? Is Steve Arnott (Martin Compston) destined for a desperately unhappy ending? And what is the deal with Ian Buckells (Nigel Boyle)?

Also, is the increasingly desperate Ted Hastings (Adrian Dunbar) as noble as he appears? Is Chloe Bishop (Shalom Brune-Franklin) a dream come true, or a nightmare in disguise? What is DCS Patricia Carmichael (Anna Maxwell Martin)’s problem? And is Marcus Thurwell (James Nesbitt) the man that Jo always believed to be her dad?

The most important question every single fan of the BBC crime series is desperate to have answered, though, is this; who the hell is H?

Line Of Duty season 6: 24 brilliant fan theories that could explain everything