TWO “dollops” of air were forced down the feeding tube of a baby boy allegedly murdered by nurse Lucy Letby, a court has heard.

The 33-year-old is said to have attacked the youngster, a newborn triplet, while she was working in the neonatal unit at the Countess of Chester Hospital.

The infant, Child P, collapsed on the morning of June 24, 2016 as his heart rate and oxygen levels dramatically dropped.

Medics managed to revive him but he needed further bouts of CPR throughout the day and died before a transfer to a specialist intensive care hospital could take place.

Letby had allegedly murdered one of his brothers, Child O, on the previous day shift – also allegedly with a fatal administration of air.

Giving evidence at Manchester Crown Court on Thursday, expert witness Dr Dewi Evans said he believed a first dose of air “destabilised” Child P on June 23.

The infant was put on nil by mouth at night after he stopped tolerating his feeds, the court has heard.

Child P suffered his first collapse at about 9.40am the next day.

Dr Evans said: “I think he had an extra dollop of air.

“I don’t think he would have collapsed but for him having an additional injection of air into his stomach.”

The retired consultant paediatrician said the effect was to “splinter the diaphragm” of Child P and compromise his breathing.

Ben Myers KC, defending, pointed out to Dr Evans that he had previously said he was “at a loss” to explain the 9.40am collapse and had suspected splintering of the diaphragm took place the day before.

He said: “You have simply shunted it along the line to – as it happens – when nurse Letby was on duty?”

Dr Evans said: “I was not putting anyone in the frame.”

Mr Myers said: “I make it plain – what you are doing again is coming up with ideas and theories to try to support the allegation rather than working in the facts we have.”

Dr Evans said: “That is incorrect.”

Mr Myers said: “What you have done is invent an extra dollop of air to try to take your theory over the line.”

Dr Evans replied: “I have not invented any dollops.

“The idea that I could get it all perfectly right from looking at all the notes is simply unrealistic.

“I was not able to speak to any member of the local staff, I was never going to get everything 100% correct.”

He said he had come to his latest conclusion after following the evidence in the trial.

Mr Myers said: “Nothing from the clinical records had changed.”

Dr Evans replied: “I am giving you my opinion.”

Fellow expert Dr Sandie Bohin said an abdominal X-ray of Child P taken in the early evening of June 23 was “abnormal” and showed an excess amount of gas.

She concluded it was “not natural air” and that it had been administered through a nasogastric tube (NGT).

Nick Johnson KC, prosecuting, asked her: “Did you come to the conclusion that in reality there was only one plausible explanation as to why (Child P) had collapsed?”

Dr Bohin replied: “My conclusion was that air had been injected into his NGT at some point, or points, and led to the splintering of his diaphragm which subsequently caused his initial collapse.

“I can’t explain why he went on to have further collapses. I can’t think of a natural cause to explain these.”

Letby, originally from Hereford, denies the murders of seven babies and the attempted murders of 10 others between June 2015 and June 2016.

The trial will not be sitting on Friday, and is expected to resume on either Monday or Tuesday next week.