A woman who murdered a baby boy she wanted to adopt has been jailed for at least 18 years.
Laura Castle shook 13-month-old Leiland-James Corkill at her home in Barrow, Cumbria, in January 2021.
She had admitted manslaughter but at Preston Crown Court was found guilty of murder and child cruelty. Her husband Scott Castle was cleared of causing or allowing the boy's death.
Castle, 38, was sentenced to life with a minimum term of 18 years.
Dressed all in black, she wept loudly throughout the hearing especially when statements were read from Leiland-James' birth mother Laura Corkill, who called her son's killer a "monster".
Mr Justice Jeremy Baker said Castle had a "selfish desire" to keep Leiland-James even though she was struggling to bond with the baby and it was a "tragedy" the Castles did not end the adoption.
Leiland-James moved in with the Castles in August 2020 when he was eight months old, having been taken into care by Cumbria County Council at birth.
The court heard the couple struggled to bond with him and Castle sent her husband messages while he was at work criticising Leiland-James, calling him vulgar names and a "moaning whinge bag" and describing how she "absolutely leathered" him.
At about 08:15 GMT on 6 January 2021, Castle called 999 to say Leiland-James was unconscious and breathing awkwardly after falling from the sofa.
He died the following day at Alder Hey Children's Hospital in Liverpool where doctors were highly suspicious of her account.
On the opening day of her trial she admitted manslaughter but said she did not mean to kill him.
She told the court she "lost her mind" as the boy was crying and she shook him to try and silence him, accidentally hitting his head against the arm of the sofa.
Neighbours said they heard a thud but no baby crying, with prosecutors claiming Castle "lost her temper" when Leiland-James spat out Weetabix.
Pathologists said "severe" force would have been needed to cause the fatal brain injuries and believed his head had been struck against a hard surface.
They said a fall from the sofa would not account for the extensive internal bleeding and likened his injuries to those suffered in a high-speed car crash.
'Lack of candour'
Cumbria County Council was aware of the bonding issues but not that Castle was using physical chastisement, with no marks or bruises seen on the boy, the court heard.
A review of the placement was scheduled for early January after a social worker said she could not approve the continuation of the adoption without further training for the Castles, but Leiland-James was killed before that.
Prosecutor Rachel Faux said Laura Castle's "lack of candour" about using physical chastisement was an aggravating feature as, had the council known of her views, Leiland-James "would never have been placed with her".
Ms Corkill said her son was taken from her "because of the risk of emotional and physical harm" but he had "actually suffered this" at the hands of his "adoptive" mother.
In a statement read to the court, she said: "I was told he would be safe and would have a good life, I was fine with that.
"Now my world is broken.
"I can honestly say this would never have happened if he was with me. An innocent life cut too short.
"It breaks me to think I will never see his face again."
In a letter issued by Cumbria Police, she said her "beautiful blue-eyed baby boy" was placed "in the home of a monster".
She said: "He was a precious baby, vulnerable and innocent, he had no voice, he could not defend himself."
Charlotte Day, who fostered Leiland-James from when he was two months old until his placement with the Castle, said her family was "heartbroken".
She said she was now questioning her fostering vocation as the "fear of ever being able to trust a prospective adopter again is such a concern".
She said Leiland-James was a "beautiful boy with the most contagious laugh" and the trial had been a "nearly daily struggle" as more information came out about what happened to him, including abuse from those "who should have been his forever family".
David McLachlan QC, mitigating, said Castle was alone and "broken" having been "isolated and ostracised in prison" following the guilty verdict, and faced the "likely end" of her marriage.
But, he said, there was only one innocent party - Leiland-James - adding Castle knew "she only has herself to blame".
He said Castle went into the adoption process "hoping to do some good" but within weeks the "situation started to unravel".
Mc McLachlan said it was clear [Castle] had been struggling with her husband working nights and the "difficulty that national and local lockdowns brought".
But, he said, there were good days as well and Leiland-James was "clearly loved" by the Castles' parents.
He said this was not the "gratuitous kind" of abuse often reflected in headlines, with which the judge agreed.
The judge said Castle had "unrealistic expectations" for the adoption and though the couple discussed ending it, was "nothing less than a tragedy that [they] did not do so".
He said Castle "deliberately lied" about her attitude towards physical chastisement knowing if she told the truth the council "would never have entrusted the care of a looked-after child to you".
The judge said Castle saw herself as "something of a victim" and blamed Leiland-James "at least partly" for the struggles which left her shouting and inflicting "some degree of physical chastisement".
He said what exactly happened on 6 January may never be known as Castle "significantly underplayed" the violence she inflicted on Leiland-James.
The judge said external injuries to the baby's face and ear were "consistent with slapping, pinching and prodding" while wounds to his lip and mouth were caused when Castle "rammed" a bottle of milk in not, as she told jurors, in an "effort to comfort him" but "in anger".
He also sentenced her to 21 months for the child cruelty charge to be served concurrently and she will not be eligible for parole for 17 years.
Det Supt Dave Pattinson, who led the investigation, said it was an "horrific set of circumstances" and obvious to medical responders at the scene a fall from the sofa "didn't add up with the nature of the injuries".
He said only Castle knew what happened that morning and had "never actually told anyone the truth".
He said she was "horrible human being" and a "manipulative liar".
Mr Pattinson said the messages she sent were "abhorrent" and called her "a bully".
Cumbria County Council said an independent review into the case was expected to conclude in July.