A retired hospital chief has denied he could have prevented the murders of two triplet boys by nurse Lucy Letby, a public inquiry has heard.

Letby injected air into the newborns on successive days at the Countess of Chester Hospital’s neonatal unit in June 2016 as part of a series of attacks from a year earlier in which she murdered seven infants and attempted to murder seven more.

The Thirlwall Inquiry into the events surrounding Letby’s crimes has heard that neonatal clinical lead Dr Stephen Brearey raised concerns about Letby with then-medical director Ian Harvey at a meeting a month earlier on May 11.

Dr Brearey previously told the inquiry that at the time he felt the number of deaths in 2015 and early 2016 were “exceptional” and highlighted to Mr Harvey that it was “unusual” that six out of nine arrests had occurred between midnight and 4am.

He said he went on to inform him that a number of reviews of care had already taken place, including with an external neonatologist, and the only common theme was the association with Letby being on duty.

Mr Harvey said that “did not accord with my recollection of that meeting” and he did not remember Dr Brearey being “that detailed or that assertive”.

Counsel for the inquiry Rachel Langdale KC said: “Child O and Child P should never have died after that May 11 meeting, should they? She (Letby) could have been off the ward and referred to the police then.”

Mr Harvey said: “I would not accept as a result of that meeting that the conversations we had and the approach that Dr Brearey and the nursing staff had, that there was anything that would have supported such action.

“Dr Brearey was entirely supportive of the action that came out of the meeting and it was highlighted that one of the actions was the reporting of any further collapses or incidents.”

He also stated to the inquiry: “At no stage during this meeting did I feel that it was being reported because there was worry that Letby was responsible for the deaths.”

Nursing managers attended the same meeting and explained there was “no evidence whatsoever against Letby apart from coincidence” and because of her qualifications she was more likely to be looking after the sickest infants on the unit.

Richard Baker KC, representing families of Letby’s victims, said the parents of Child O and P regarded the meeting as a “missed opportunity” to avoid the deaths of their sons.

Mr Harvey said he did not accept that proposition.

Mr Baker said: “Did you not see anything significant about the fact that all of these deteriorations were occurring on night shifts?”

Mr Harvey replied: “There is evidence that standards of care are lower at weekends and at night…and that would have been my initial concern.”

He said that an Imperial College research paper had found increased mortality at weekends and added: “But it’s accepted that the risk is also greater at night. That almost certainly reflects different staffing levels.”

Letby was eventually moved to an administrative role in July 2016 after all the consultant paediatricians met with executives after the deaths of Child O and Child P and voiced their fears the nurse may be deliberately harming babies.

One of the greatest regrets of my career is the breakdown in communication between the executives and paediatricians, and with me in particular. I recognise how intense and difficult a situation that was

Mr Harvey went on to commission a series of reviews into the increased mortality as Cheshire Constabulary was not called in to investigate the matter until May 2017.

Consultants pressed on with expressing their concerns amid plans in early 2017 to return Letby to the neonatal unit, the inquiry has heard.

Mr Harvey said: “One of the greatest regrets of my career is the breakdown in communication between the executives and paediatricians, and with me in particular.

“I recognise how intense and difficult a situation that was.”

Asked by Ms Langdale if he accepted that he, chief executive Tony Chambers and director of nursing Alison Kelly created an “atmosphere of fear”, he replied: “I did not seek to create an atmosphere of fear. That was completely contrary to how my practice had been up until that time.

“I have accepted there were one or two emails that I inappropriately worded.”

Ms Langdale said: “It was an us-and-them situation, wasn’t it? The executives versus the consultants.”

Mr Harvey replied: “It is one of the biggest regrets that at this stage it was reaching this situation.”

Letby, 34, from Hereford, is serving 15 whole-life orders after she was convicted at Manchester Crown Court of murdering seven infants and attempting to murder seven others, with two attempts on one of her victims, between June 2015 and June 2016.

The inquiry, which is being held at Liverpool Town Hall, is expected to sit until early 2025, with findings published by late autumn of that year.