A man who crushed a three-year-old boy to death with a car seat has been jailed for more than seven years.
Stephen Waterson, 26, inflicted irreversible brain injuries on Alfie Lamb, his girlfriend’s son, who was sat in the footwell behind him in 2018.
Waterson initially denied manslaughter but changed his plea to guilty before a retrial in September.
Alfie had been at his mother Adrian Hoare’s feet at the time. She was jailed for child cruelty in May.
Sentencing Waterson, Mr Justice Kerr said he was “cunning, manipulative, threatening, and controlling”.
Justice Kerr said: “I do not find you were annoyed with Alfie and moved your seat back because of that annoyance.”
But he said he was satisfied he moved his car seat back twice “for your own comfort”.
The judge accepted character references from Waterson’s parents, who were in court, and agreed he was “not all bad”.
Waterson, described by police as “arrogant, selfish and deeply unpleasant”, had lied to detectives about what happened and threatened his girlfriend and two friends who were also in his Audi convertible at the time.
Mr Justice Kerr sentenced Waterson to five years and six months for the manslaughter.
He was handed a further two years for intimidation and 18 months for conspiracy to pervert the course of justice, to run concurrently.
Hoare, 24, of Gravesend, Kent, watched as her son was crushed in front of her and then lied to protect her boyfriend.
She was sentenced to two years and nine months but cleared of manslaughter.
During her trail the jury heard Alfie was crying during a return journey from a shopping trip to Sutton, south London, on 1 February 2018.
When he continued to moan, Waterson reversed twice, saying, “I won’t be told what to do by a three-year-old”, the court heard.
The maximum space in the footwell was 30cm, and, at the touch of a button, that could be reduced to just 9.5cm, the Old Bailey was told.
Alfie collapsed in the car and died in hospital three days later from irreversible brain injuries.
His mother eventually confessed what happened to her half-sister Ashleigh Jeffrey in a taped conversation handed to police.
Prosecutor Duncan Atkinson QC read out a victim impact statement from Ms Jeffrey.
She said: “He [Alfie] was always smiling. His death has had such a profound effect on my life.”
It is the first time anyone in the UK has died from crush asphyxiation as a result of an electronic car seat, police said.