A driver who witnessed the car of Mark Gordon and Constance Marten on fire has said he fears their baby may still be alive if he had stayed with the vehicle.
Ken Hudson was following the couple's Peugeot 206 when it caught fire on the M61 motorway in Greater Manchester.
Gordon and Marten pulled over to the hard shoulder where they both got out of the car and ran, jurors at the Old Bailey were told.
Footage filmed by Mr Hudson showed the car alight with smoke billowing out of it.
Mr Hudson said he noticed Marten carrying a baby - who was to have been named Victoria - and asked if it was okay, to which she replied: "She's fine."
Marten told Mr Hudson he was fine to leave the scene, and as he did so, he "put his hand on the baby's head and said God bless", he told the court.
Marten's passport, "burner" phones and a placenta wrapped in a towel were discarded in the wreckage, jurors were told.
Asked by prosecutor Tom Little KC if the baby had been warm to the touch, Mr Hudson said it seemed cool, "but it was winter", he added.
Asked if he had heard any noise from the baby or seen any movement, he replied: "None whatsoever."
Mr Hudson said he was "cut up because I believe that if I stayed with the vehicle, the baby may be still alive".
Couple decided to 'remove ourselves from society'
A high-risk missing persons inquiry was then launched and the couple became front-page news, the court was told.
Marten later told officers she and Gordon ran away with the baby after their car "exploded" assuming police would take their daughter away, then decided to "remove ourselves from society" when people started to recognise them on the streets.
Earlier, a defence barrister claimed the baby was kept "warm and dry, and was fed".
Baby 'well cared for', defence argues
Outlining the defence argument, John Femi-Ola KC, representing Gordon, said the baby was "well cared for" and "did not require medical assistance".
A jury at the Old Bailey was previously told how "wealthy" Marten, 36, and Gordon, 49, feared their daughter would go into care after their four other children were previously taken away by social services.
The couple, of no fixed address, deny manslaughter by gross negligence, perverting the course of justice, concealing the birth of a child, child cruelty and causing or allowing the death of a child.
The trial continues.