The jailing of Stephen Waterson for the manslaughter of Alfie Lamb brings the legal chapter of this tragic story to a close.
Alfie's mother Adrian Hoare was convicted of child cruelty in February. She had the three-year-old between her feet in the car's rear footwell when he was crushed to death as Waterson moved his seat back. The toddler died clutching his mother's little finger.
Legal sources say she had agreed to testify against Waterson at his retrial for manslaughter, which he avoided by pleading guilty to the charge.
The history of the case makes it clear that for almost all of Alfie's short life, he had been surrounded by people who were at best careless of his safety, and at worst reckless with his life.
Stephen Waterson had been the father figure in Alfie's life for a couple of years.
The 26-year-old's Facebook page said he had two daughters, both with other women, and at the time of Alfie's death he was working at a nightclub in Kingston.
The jury heard evidence that he was a jealous and controlling man with a history of violence. All three of the other adults in the car with Alfie that day lived in Waterson's Croydon flat and all testified that they were scared of him.
Adrian Hoare told the Old Bailey: "It was like you never knew how he was going to react to things. He could kick off about something, get really angry."
He had three assault convictions going back to 2014. The police have also confirmed that a former girlfriend made complaints about Waterson's treatment of her in 2015 and again in 2017.
In 2012 and 2013, girls aged 14 and 15 accused him of making threats and sending them abusive messages when he was at least five years older than both. Another girl told police he had been violent towards her in 2012, although charges were never brought in those cases.
Waterson and Hoare began their relationship in 2016 when Alfie was two.
The court heard that soon after becoming pregnant again a year later, Hoare discovered her partner was having relationships with two other women and confronted him.
She told the jury that Waterson had persuaded her to get into a car with him and then drove off at speed, saying: "I'll kill myself, you and that baby." She managed to make him stop and the police were called.
But in his sentencing remarks Mr Justice Kerr said he found that incident "not proved".
The jury also heard evidence of his controlling behaviour towards Hoare and the others living in his flat.
He had never given her keys to the homes they had shared. He had sold her phone so she had to use one of his, enabling him to access her Facebook account. Her benefit money was paid into his bank account, to which she had no access.
The court heard she had almost no contact with her family and Waterson controlled her access to friends. "He didn't really like me speaking to anyone," she said.
None of the others in the flat were allowed keys either and the jury heard Waterson did not like them to be there without him. So when he wanted to go shopping in the car, he made them all go in his four-seater Audi convertible with the children in the footwells.
Waterson told those in the car to lie about what had happened, warning them that he knew "ways to make people disappear" and "I'll get rid of anyone who gets in my way".
He often mentioned his "powerful parents", the former Conservative minister Nigel Waterson and his wife Barbara Judge, who adopted him when he was eight.
He made sure to tell the police about them. One or both of his adoptive parents sat in the public gallery throughout the trial.
In court, he denied trying to use their status to make him appear "untouchable". But Hoare said his boasts about his family made her feel "little compared to him. I didn't really have anything".
It's a sign of how chaotic Hoare's family life had been that Waterson was one of the more stable parts of it.
She told the court she'd left a mother and a violent stepfather who both had addiction issues. Then she fell out with her dad, who she said had also been violent. She left his home aged 15 and lived for a time in a hostel.
Three years later when Alfie was born, she was living with a man 15 years older than herself, Richard Lamb, who was named on Alfie's birth certificate as his father. She said he too had drug and alcohol problems and was violent towards her.
After he moved out of their home in Chatham in 2015, Lamb returned and set fire to it during the night. He was given a three-year prison sentence for arson after a trial in which Hoare testified against him.
Hoare admitted in court that she was not a "completely perfect" mum, but the jury heard that social services had never questioned her fitness as a mother.
Alfie was a normal size and weight for a child of his age with no evidence he had ever been abused.
There were allegations that Hoare had been seen to slap Alfie - which she denied - but she admitted he had been placed in the rear footwell of cars regularly, which she knew was unsafe.
Text messages and overheard conversations presented in court showed both she and Waterson would often swear about the toddler.
Even as Alfie was being treated in intensive care, she texted Waterson: "If the worst does happen you still won't lose me."
Det Ch Insp Simon Harding, who led the investigation, said it appeared that she "was more concerned about being back with Waterson than being with her own child".
But while Alfie lay in hospital, Waterson was texting four other women he was trying to meet up with.
The social services were first made aware of Hoare and Alfie when they were living in Kent with Lamb.
Medway Safeguarding Children Board has been conducting a serious case review involving all the various agencies, police and social workers involved with the case. It is expected to report by the end of the year.
It is hoped the review will shed some light on how a vulnerable little boy came to be living in circumstances that caused his death.