Line of Duty: the Jo Davidson Family Mystery Revealed

We now know who Jo Davidson related to and the sad story of her estranged family. Spoilers and speculation ahead

Line of Duty Kelly Macdonald Jo Davidson
Photo: World Productions

Warning: contains spoilers for Line of Duty series 6 episode 4

Nothing is standalone in this Line of Duty series six; everything is linked back to what’s gone before. Ryan Pilkington, Terry Boyle, Steph Corbett, Ian Buckells, Jimmy Lakewell, Blackthorn Prison, Lee Banks, even Jackie Laverty… all of them ‘previously on’ characters who’ve made a reappearance and dragged the past back with them. 

It should come as no surprise then, that the series six guest lead played by Kelly Macdonald also has a significant link to the past. The end of episode four revealed that Acting Det Supt Jo Davidson is the blood relative of a key character already known to AC-12. In episode five, we learned that person was Tommy Hunter, the former OCG leader we first met back in series one and two. And that, as Steve told Kate, isn’t the worst of it. Jo’s DNA showed an extremely high match and runs of homozygosity, indicating that her parents were related making her the product of incest.

“I don’t have a family”

Line of Duty series 6 episode 1 Jo Davidson family photo

In episode one, when Farida complained that Jo was ashamed of their relationship because she’d never been introduced her Jo’s family, Jo replied “I don’t have a family.” Later, a frustrated Jo threw a glass of wine at a photograph that appeared to show a younger her with her mother. That set fans pondering a possible link between Jo’s estranged family and the mysterious hold the OCG had over her. Had Jo’s mother been kidnapped? Was Jo being blackmailed about something the OCG had over a family member? Were her corrupt actions driven by family loyalty?

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When AC-12 expanded the forensic search of Farida Jatri’s home, they were hoping to find evidence of Davidson’s DNA to support the theory that Farida was telling the truth about them having lived together and Davidson having framed her by planting the OCG-linked burner phones. They found that alright, along with a surprise extra. When the DNA deposits discovered at Jatri’s were run through the system of police databases, analysis detected that Davidson shared DNA with Tommy Hunter.

Tommy Hunter

Line of Duty Tommy Hunter series 1

There’s been a fan theory linking Jo and Tommy Hunter since the very beginning of series six, on account of their shared Glasgow backgrounds. Many suspected that Jo is secretly Tommy’s daughter, but their relative dates of birth made that questionable, until the incest revelation. Thanks to a Post-It Note next to Hunter’s photo on the AC-12 evidence board spotted by fans in episode five, the current theory runs that Tommy is Jo’s father and uncle. He was born in 1965, presumably raped his own sister at the age of 13-14, and Jo, born in 1979, was the product of that incestuous abuse. Jo’s next-of-kin is listed on her police record as Samantha Davidson, who is now dead, and the mother in episode one’s framed photograph (see above).

If you don’t remember Tommy, he was the former leader of the OCG who blackmailed Tony Gates in series one, and was revealed to have recruited DI Dot Cottan as a teenager and planted him as a corrupt officer on the force. Tommy was a paedophile who abused young boys in an OCG-run child sexual abuse ring in Sands View children’s home. After Tony Gates recorded a confession from Tommy before killing himself, Tommy was arrested and given immunity in exchange for providing information. In witness protection as “Alex Campbell”, the OCG made two attempts on Tommy’s life in series two, the second one successful.

All of which leaves the question: with Tommy dead by the OCG’s hands back in series two, what power do they have over Jo now? Was she unaware of her father’s identity and the circumstances of her birth until the OCG threatened to make it public? Fearing a public scandal (after all, this is certainly something the tabloid press wouldn’t leave alone if discovered) and the possible loss of her police role, is that why Jo has reluctantly been following OCG orders?

DS John Corbett

Stephen Graham in Line of Duty

We now know that another pre-existing fan theory based on that framed photograph of Jo’s mother is wide of the mark. Some fans thought that the woman in Jo’s picture was Anne-Marie McGillis, the mother of series five UCO-turned-rogue-bent-copper-hunter John Corbett, which would have made Jo his sister. When Anne-Marie was killed by the IRA in 1989 for passing information to the RUC, John was sent to Liverpool and raised by his aunt and uncle. The theory went that Jo would have been sent to other relatives in Glasgow, hence the ‘siblings’ having such different accents.

Put simply, it never checked out. For a start, Ted Hastings was close friends with Anne-Marie McGillis, and knew all about her wee lad John, but never mentioned that she had a daughter. Secondly, Jo Davidson’s date of birth is listed as 22/4/79 and John Corbett’s as 3/6/1979 – the same year. Thirdly, if you really look at those two photographs, despite some similarities, it’s not the same woman, though we’d put money on the fact that the new photo was designed to have a resemblance. 

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DS Danny Waldron


Another defunct theory was the idea that Jo could have been related to series three guest lead Danny Waldron, whose mother died when he was young, so he was forced to move around the country. Danny left the city to move up north with his father and stepmother, but when that didn’t work out, he was placed back locally, in the Sands View children’s home. That’s where he and the other boys were routinely sexually abused by an OCG-paedophile ring including police officers and politicians, prompting Danny’s revenge list murders. There’s no mention of Waldron having had a sister, but there was a link between him and Davidson. Danny Waldron’s home address in series three was 5 Croxford Street. When Chloe is taking the team through the surveillance on Ryan Pilkington (around the 29 minute mark), it’s mentioned that Jo Davidson’s home address is also on Croxford Street. Just a coincidence or a red herring, it seems.

The Scottish connection

Line of Duty ACC Hilton

Previous key characters ACC Derek Hilton, DS Jayne Akers and DCC Mike Dryden were, like Jo, also from Scotland, which had suggested a possible link to Jo Davidson before we knew the real answer. Hilton was a bent copper who apparently committed suicide at the end of series four (but was much more likely killed by the OCG) after he conspired with Jimmy Lakewell to frame Michael Farmer for murder. Dryden left the force at the end of series two after being convicted of perverting the course of justice when he lied about getting a speeding ticket in order to have an alibi for engaging in a sex act with teenager Carly Kirk, who was being exploited by Tommy Hunter, Jo’s father/uncle.

Line of Duty continues next Sunday the 25th of April at 9pm on BBC One.