A man has admitted crushing a three-year-old boy to death by reversing his seat as the boy sat in a car footwell.
Stephen Waterson, 26, killed Alfie Lamb - his girlfriend's son - in February 2018.
Waterson initially denied manslaughter but changed his plea to guilty ahead of a retrial at the Old Bailey.
In May, Alfie's mother Adrian Hoare - who watched as her son was crushed - was jailed for two years and nine months for child cruelty.
Hoare was cleared of manslaughter while a jury failed to reach a verdict on the same charge for Waterson.
The court had heard Waterson had been annoyed at Alfie's crying on a journey back from a shopping trip and moved his seat into him as he sat in the footwell at his mother's feet.
When Alfie continued to moan, Waterson reversed again, saying, "I won't be told what to do by a three-year-old," Hoare told jurors.
Alfie collapsed in the car and died in hospital three days later from irreversible brain injuries.
In their trial earlier this year Hoare, of Gravesend, Kent, told a string of lies to protect her boyfriend, claiming she had been in a taxi, while Waterson fled in the Audi.
Det Ch Insp Simon Harding said: "Stephen Waterson and Adrian Hoare, even after Alfie died, were more concerned about being together.
"Stephen Waterson was concerned the real story never came out. He went on to intimidate and assault people."
Waterson also gave officers a false name, a false statement and sold the Audi.
Hoare eventually broke her silence and told her half-sister Ashleigh Jeffrey what happened in a taped conversation handed to police.
Jurors were also told Waterson had three previous convictions for attacking an ex-girlfriend and his sister's husband.
Waterson, the adopted son of former Conservative minister Nigel Waterson, admitted manslaughter by gross negligence on what was set to be the first day of his retrial.
He was remanded in custody to be sentenced on 9 September.
Det Ch Insp Harding said: "For a three-and-a-half-year-old to be crushed by something so strong and no-one helping, it's a shocking way to die.
"Stephen Waterson has come across as a selfish, abhorrent individual".
Angela Moriarty, from the Crown Prosecution Service, said: "This was a harrowing and difficult case for all those involved, but finally justice has been served for Alfie."
Speaking after the hearing police revealed social services had been involved in Alfie's care and that the Medway Safeguarding Children Board is conducting a serious case review.