Skip to main contentSkip to footer

Who is Jo Davidson related to in Line of Duty? Best theories

Episode four ended on a major bombshell

lod jo davidson relative
Francesca Shillcock
Senior Features Writer
Updated: 18 April 2021
Share this:

It's safe to say Line of Duty almost broke the internet on Sunday evening after episode four had everyone theorising on who DCI Jo Davidson's mystery relative is. Ahead of episode five, we have put together the internet's best theories on who on earth was in that report... 

MORE: Line of Duty season six: HELLO! breaks down episode four

The team at AC-12 discovered that the detective, played by Kelly Macdonald, had DNA deposits at PC Farida Jatri's home, but when evidence was run through the police database, another match was brought to light exposing that Jo has a key family tie within the system  – and so begins the guessing!

WATCH: HELLO! breaks down episode four of Line of Duty - here's what you might have missed!

Tommy Hunter 

Remember him? Tommy was the leader of the OCG pack for much of Line of Duty's early episodes. Played by Brian McCardle, Tommy later began working as an informant for the police to avoid prosecution but was subsequently injured in the ambush which formed the arc of series two (and killed DS Jayne Akers). He later died in hospital at the hands of his own men for becoming an informant.

MORE: Tommy Hunter: everything to know about Line of Duty character

But why would Jo's relation to Tommy Hunter be significant, considering his death? One fan wrote on Twitter: "I have been thinking about this far too much, but my fave theory is that Jo is Tommy Hunter's daughter, and being blackmailed by the OCG to pay off his debts #lineofduty #LineofDuty6."

tommy 1© Photo: BBC

Tommy Hunter was the former leader of the OCG

Matthew 'Dot' Cottan

This leads nicely onto the next contender – Matthew 'Dot' Cottan, played by Craig Parkinson. It was Dot (AKA The Caddy) who ordered the ambush to kill Tommy Hunter once discovering he was in Witness Protection and leaking intelligence to the police.

If Jo is related to Dot, then it makes sense that Jo would now be in the pocket of the OCG – given Dot's previous history of being an officer under pressure from organised crime. Could she be following in his footsteps? Another fan is convinced of this idea, tweeting: "My tin foil hat is on... Jo is related to Cottan. #LineOfDuty." 

dot lod© Photo: BBC

Is Dot the mystery relative?

Carly Kirk 

Carly Kirk went missing in season two and it was Lindsey Denton (played by Keeley Hawes) who was investigating her disappearance. It then transpired that former Detective Chief Constable Mike Dryden (Mark Bonnar) was engaging in sexual activity with the teenager and was sent to prison.

MORE: Line of Duty's Adrian Dunbar sets record straight on H's identity

MORE: Line of Duty fans spot major mistake in episode three

It then turned out that Carly was presumed 'murdered' by the OCG, but her body was never found. If she is related to Jo, then her position within the police then makes her vulnerable to OCG blackmail. Time will tell… 

carly kirk© Photo: BBC

Carly Kirk is still missing

DCC Mike Dryden

Speaking of Dryden, could he be the relation to Jo? Both are Scottish, so there's that, but beyond nationality we're not sure if this one lets up. It's certainly possible, as one fan mused on Twitter: "My moneys on Jo's blood relative being former DCC Mike Dryden... currently serving time for perverting the course of justice, taken down by AC-12 themselves a few seasons back!  Both Jo and himself played by Scottish actors #LineOfDuty." 

mike dryden© Photo: BBC

Remember Mike Dryden?

John Corbett 

Series five saw the fantastic Stephen Graham make his mark on the show as John Corbett, the new 'boss' of the OCG. However, it transpired that John was, in fact, a detective deep undercover exposing organised crime intelligence. It was his blown cover that got him killed towards the end of the series at the hands of newly recruited MIT junior Officer Ryan Pilkington. 

MORE: Line of Duty viewers have intriguing new theory on Ian Buckells

Many reckon John and Jo are related through their mother, Anne-Marie McGillis, after spotting an interesting photo in Jo's apartment. One viewer noticed the similarity: "The picture Jo Davidson threw a glass at... and a picture of John Corbetts Mum Anne-Marie McGillis, who was a police informant and would have been on the database. I'll take that vacant position in the team now, Jo Davidson... #LineOfDuty." 

stephen graham

Stephen Graham as John Corbett

Jake Kilorgan

Jake was one of the criminals that took part in the robbery at the Bookies during episode one. It was Jo Davidson that spotted the crime, which subsequently led to a delay in arresting a crucial suspect in the murder of Gail Vella. A fan on Twitter wrote: "I reckon Jake (questioned about the armed robbery) is Jo's brother. He's going to play a big part because his name has been in the credits since episode one and the other robbers' haven't. And she panicked when one robber got shot." 

We can't help but think that Jake also has a strong resemblance with Ryan. Could the two both be related to Jo? This would certainly point to strong links between the police and organised crime. 

One thing's for certain – we cannot WAIT for next Sunday. 

Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.

Sign up to HELLO Daily! for the best royal, celebrity and lifestyle coverage

By entering your details, you are agreeing to HELLO! Magazine User Data Protection Policy. You can unsubscribe at any time. For more information, please click here.