Lylah Aaron was described as "bubbly and outgoing"
A man who murdered his girlfriend's young daughter when he was supposed to be looking after her has been ordered to serve at least 20 years in jail.
Delroy Catwell was alone with Lylah Aaron, three, at their Sheffield home when he attacked her, at one stage smashing her head on a bedroom wall.
Catwell, 31, was found guilty of murder at Sheffield Crown Court on Tuesday.
Jailing him for life, Mrs Justice Nicola Davies said it was "difficult to conceive of a greater abuse of trust".
She told the DJ at Wednesday's sentencing hearing: "The injuries sustained by Lylah on the 8th of February to her head, ribs and abdomen would have required considerable force.
Delroy Catwell was told he will serve at least 20 years
by a judge at Sheffield Crown Court
"This slight child would have been wholly defenceless in the face of such a sustained assault.
"Compounding your actions, you allowed Lylah, who would have drifted into an unconscious state, to remain at home.
"You made no attempt to call for medical aid. For a matter of hours you knew that within the house was a badly injured young girl for whom you were responsible."
During the two-week trial, the jury heard Catwell, Lylah and her mother Precious Chibanda shared a house in Beck Road in Shiregreen, Sheffield.
Head smashed against wall
On 8 February, Catwell was left in charge of Lylah as her mother went to work.
The court heard Ms Chibanda returned to find her daughter in bed and only later realised she was unconscious.
She had suffered head injuries and died later in hospital.
Examination of a bedroom wall by forensic experts showed Lylah's head had been smashed against it.