“FORCEFUL CPR” could not explain liver damage suffered by a baby allegedly murdered by nurse Lucy Letby, a court has heard.

Letby, 33, is said to have attacked the new-born triplet on a day shift on June 23, 2016 at the Countess of Chester’s neo-natal unit following her return from a holiday to Ibiza.

Child O is alleged to have been one of 17 babies she targeted between June 2015 and June 2016.

He was born in good condition, Manchester Crown Court has heard, until he suddenly collapsed two days later in the care of Letby and went progressively downhill as medics failed to revive him.

Paediatric pathology expert Dr Andreas Marnerides had told jurors he concluded Child O died because of “inflicted traumatic injury” to the liver, as well as receiving fatal injections of air into the stomach and bloodstream.

He compared the extent of the liver injuries to those suffered fatally by children involved in road traffic accidents and non-accidental assaults.

On Thursday, March 30, Ben Myers KC, cross-examining, said: “Can you assist with how little force could be involved?”

The consultant at London’s St Thomas’ Hospital said: “I think there is no way of measuring a force in a baby because we don’t conduct such experiments on babies.

“I have never seen this type of injury in the context of CPR so I would say the force required would be of the magnitude of that generated by a baby jumping on a trampoline and falling.”

He agreed that smaller internal bruising to the liver sustained by Child O’s triplet brother Child P – who Letby is alleged to have murdered the next day – could be capable of being caused by CPR.

But asked if “rigorous” chest compressions could be the cause of the internal bruising in Child O’s case, Dr Marnerides said: “I don’t think so, no.

“This is a huge area of bruising for a liver of this size. This is not something you see in CPR.”

Mr Myers said: “So you don’t accept the proposition that forceful CPR could cause this injury in general terms, do you agree it cannot be categorically excluded as a possibility?”

Dr Marnerides replied: “We are not discussing possibilities here, we are discussing probabilities.

“When you refer to possibilities, I am thinking for example of somebody walking in the middle of the Sahara desert found dead with a pot and head trauma.

“It is possible the pot fell from the air from a helicopter. The question is ‘is it probable?’ and I don’t think we can say it is probable.”

Mr Myers asked: “Is it possible in your opinion for at least some of what we see in the damage to the liver arising from the insertion of a cannula?”

The consultant said: “I would consider it extremely unlikely. I would expect some kind of perforation injury.”

Earlier, Dr Marnerides said the most likely explanation for the death of Child P was excessive air injected via a nasogastric tube into his stomach.

Letby, originally from Hereford, denies the murders of seven babies and the attempted murder of 10 others.

The trial continues on Friday, March 31. The Standard will be providing live updates throughout the day.