A bus passenger wept as she told a court how she fought to save the life of a three-month-old baby while the little girl’s mother sat “relaxed” and on her mobile phone.

Rosalin Baker, 25, and her partner Jeffrey Wiltshire, 52, are accused of murdering their daughter Imani and covering it up by staging her death on board a bus on September 28 last year.

The Old Bailey heard how Baker had boarded the 25 bus in Romford Road, close to the junction with First Avenue, with Imani strapped to her in a sling, and sat down in the back half of the double decker bus.

Fjoralba Shmitz, who was listening to music on her headphones while on her way to work, said that she became aware of Imani’s lack of movement when Baker got her attention by beckoning.

“She said ‘there’s something wrong with my baby’,” Ms Shmitz told the court through an Italian interpreter.

“I saw the baby’s face. I touched her left cheek. It was cold. I straight away tried to take the baby out of the sling.

“I took the baby and I laid her down on the bus seat. The baby was not breathing. I tried to help but I didn’t manage to do so. The baby had lips that were cold.”

Ms Shmitz, who became emotional in the witness box, added: “At a certain point, I took the child in my arms. I went up to the bus driver and asked him to call the police and the ambulance.

“I thought that the baby was dead. I took the baby back to the bus seat and a lady - a think she was Spanish - started praying.”

The bus driver, Jerry Ballington, pulled over in the bus stop in High Street, Stratford, near the junction with Carpenters Road, the court heard.

Jurors were told that he pressed first the red emergency button to raise the alarm with the control centre, then when that did not work, pressed the green button to speak to them directly.

They also heard how he hadn’t thought anything unusual about the situation when Baker boarded the bus earlier that morning, or when Wiltshire waved her and Imani off.

In a statement read out in court, he said: “I saw him pat her on the shoulder as she got on which I thought was his way of saying bye.”

Mostafa Rahman, who had ridden the bus from the Little Ilford Lane stop on the top deck, came down to the lower deck to get off at the Carpenters Road stop and noticed what was going on.

He told the court how he used his phone to call an ambulance before passing it to another passenger - Viviana Caidedo, who Ms Shmitz referred to in her testimony as the Spanish lady - to allow the operator to instruct her how to perform CPR.

Asked by prosecutor Duncan Atkinson QC why he had not performed CPR himself, he said: “I wasn’t really confident. I’ve never done it before. She was trying to help. She said she did it before or something.”

The court also heard that it was initially unclear to passengers on the bus who the mother of the baby was.

Ms Shmitz said of Baker: “She did not have any reaction. She was not crying, she was not shouting, she was not speaking and there were other passengers on the bus too who were asking if it was my son.”

Cross examining, Icah Peart QC said: “This is obviously a very shocking and distressing episode for you, but right from the very start, is it correct that the mother of the child appeared to be completely detached from what was happening to her child?”

Ms Shmitz replied: “Dear Mr lawyer, a detached person does not stay on the phone in her hand when her daughter is not being well.

“I believe when I was sitting down and she made a sign, she was on the phone to someone, so I don’t know. As far as I’m concerned, she seemed very relaxed.”

Baker and Wiltshire, of Morris Avenue, Manor Park, deny murder and causing or allowing the death of a child.

The trial continues.