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Season six of Line Of Duty has left fans with more questions than answers, with viewers flocking to Twitter to question what exactly is DCI Jo Davidson is up to, whether Kate Fleming has really left AC-12 and who is H?

Here, MailOnline examines some of the most prominent fan theories  

Kate Fleming HASN'T left AC-12 and is working undercover   

One of the most shocking discoveries was AC-12's Kate is now working with a new team- with some fans suggesting she could even be the infamous H.

While chatting to her new gaffer DCI Davidson, Kate said: 'I got fed upon nicking coppers, I'd rather go after the psycho who murdered Gail [Vella].'

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But despite seeming confident in her new role, some viewers were left wondering if all was at it seems and theorised that Kate could still be undercover for AC-12.

Even after she tipped off Davidson and incurred the wrath of Ted Hastings, fans have continued to speculate that she is so deep undercover that even Hastings is having to keep her true agenda secret.  

Kate Fleming HASN'T left AC-12 and is working undercover: Is it true? The jury is still out on this one

Kate Fleming HASN'T left AC-12 and is working undercover: Is it true? The jury is still out on this one 

DCI Jo Davidson is being blackmailed by an Organised Crime Group  

Jo has already survived a grilling from AC-12's top team and appeared to clear her name when it was ex-girlfriend PS Farida Jatri who seemed to have taken part in corruption.

However, Jo was seen hitching a ride with known bent copper Ryan Pilkington and taken to collect a burner phone, making her look suspicious once more.

Fans, however, are convinced the DCI is being blackmailed by an OCG, following her emotional outburst when she was summoned to pick up a new burner.

DCI Jo Davidson is being blackmailed by an Organised Crime Group: Is it true? After her car park outburst it seems increasingly likely

DCI Jo Davidson is being blackmailed by an Organised Crime Group: Is it true? After her car park outburst it seems increasingly likely

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DCI Jo Davidson's mother is Anne-Marie McGillis

Fans speculated over who Jo's mother could be after she was seen in a photograph in the first episode.

Many theorised her mother has something to do with season five character John Corbett's [Stephen Graham] mother Anne-Marie McGillis, who was killed by an Irish Republican paramilitary group sometime after 1989.

DCI Jo Davidson's mother is Anne-Marie McGillis: Is it true? There simply isn't enough evidence yet to determine on way or the other

DCI Jo Davidson's mother is Anne-Marie McGillis: Is it true? There simply isn't enough evidence yet to determine on way or the other  

Gail Vella is still alive

Although season six has centered around the murder of journalist Gail Vella,

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