A mother calmly acted out the death of her 16-week-old daughter on a bus to cover up the child's murder at home, a court has been told.
Rosalin Baker, 25, was given the "thumbs up" by her 52-year-old boyfriend Jeffrey Wiltshire to stage the charade.
Jurors heard she boarded the number 25 in Stratford, east London, holding the infant's body and proceeded to ask other passengers for help, telling them her baby had just fallen ill.
However, Imani was born prematurely and was already dead after being subjected to at least three severe attacks and flung on the floor, the court heard.
The baby had a broken wrist from her arm being "pulled or twisted" and at least 40 rib fractures from her chest being squeezed as she was shaken.
She also had a fractured skull and brain injury "as the result of being thrown against the floor or an upright surface" which led to her death, prosecutor Duncan Atkinson QC told the Old Bailey.
He said: "During the course of the bus journey, Baker suddenly sought help from her fellow passengers for a problem that she said she had just identified with her daughter.
"Those members of the public, presented with the nightmare of an infant who was not breathing, did all they could to help.
"They were panicking and distressed. In contrast, Baker was noted to be cold and calm.
"As those members of the public, and then paramedics, sought to help her child, Baker sat to one side and sought to contact first her sister and then Wiltshire."
Imani was pronounced dead in hospital and her parents went on to give a false account of what happened to police, even denying that Wiltshire was the father, the court heard.
Baker had taken the infant to live with Wiltshire in his bedsit in Newham, east London, after leaving her mother's home in Colchester, Essex.
Mr Atkinson said the injuries inflicted in those days would have caused the baby "very significant pain and distress" which would have been obvious to any parent.
But he said neither Baker or Wiltshire sought medical help.
Mr Atkinson said the "only realistic candidates" for causing the baby girl's death were Wiltshire and Baker.
He said if they were both not responsible for the fatal injury, at least one of them failed to intervene.
Jurors heard Baker had been receiving "intervention" from medical professionals and social services from the birth up until the last week of the Imani's life.
Baker and Wiltshire deny murder and causing or allowing the death of their child on 28 September last year.
The trial continues.