A nursing boss became tearful as she accepted police should have been called earlier when suspicions were raised over Lucy Letby at the Countess of Chester Hospital.

The Thirlwall Inquiry into the events surrounding the crimes of Letby heard former neonatal unit manager Eirian Powell deny that Letby was a "particular favourite" of hers.

Documentation submitted to the inquiry showed, during Letby's grievance investigation, an interview conducted by Dr Chris Green in October 2016 had Ms Powell state Letby was "so amenable and flexible, one of my best nurses" and her practice was "second to none".

Richard Baker KC, representing several of the families of Letby’s victims, referred to an incident where a nurse had complained about Letby's "very, very unusual" behaviour following the death of Child C in June 2015, where she spent "all her time in and out of the family room focusing in on the family who were caring for their dying child", a job which should have been done by Child C's designated nurse, and by doing so had "put the life of another baby at risk."

He added Letby's designated baby "deteriorated during the course of the night and the care needed to be escalated the following morning", and Letby had "ignored the instructions of [the nurse] over and over again".

Asked if any action had been taken against Letby over this, Ms Powell said: "I don't recall. I would have documented something surely in her, in her [HR file] and it's not – I don't think it's there anyway...so I just don't recall it."

Ms Powell remembered speaking to the nurse who complained and "discussed it".

Mr Baker asked: "Now, this is quite a serious thing to happen, isn't it?"

Ms Powell replied: "Yes."

Asked if Letby was a "particular favourite of hers", Ms Powell replied: "Not at all, I don't have favourites, at all. I don't, I didn't. There was nobody on the unit that I favoured. That wasn't part of who I am. I don't have favourites."

Ms Powell said she did not go to staff social events because she wanted to “remain impartial” in her management role but accepted that she to went London with Letby and other nurses to see The Bodyguard in 2013.

She told the inquiry: “We didn’t all go obviously. Somebody has to stay behind to do the shifts.”

The inquiry heard that Ms Powell had said Letby was “quirky, but then I like quirky”.

Mr Baker said: “Did you have a particular connection with Letby?”

Ms Powell said: “No, we are all different. It takes a certain personality to work on the unit. Over the years that I was there it was the quirky ones that actually survive the unit. Quirky is different from the normal, perhaps seeing things a little differently.”

Mr Baker went on: “The fact of the matter is when it came to Lucy Letby you favoured her, you gave her favourable treatment?”

Ms Powell said: “No, not at all in the slightest.”

Asked why, in the grievance investigation interview, Ms Powell had said Letby was "100% innocent", Ms Powell replied: "Well, I couldn't believe that she had done it?"

Mr Baker noted Ms Powell had, in the same interview, suggested consultants Stephen Brearey and Ravi Jayaram had "brainwashed the other consultants" over their concerns about Letby.

Ms Powell replied: "No, I know, but at the time we didn't think that this was going to - that I had to watch what I was saying and how I was saying it."

Evidence submitted to the inquiry showed Ms Powell had conducted a neonatal review in May 2016 which had looked at babies which had died on the unit. Ms Powell accepted, following a question by Mr Baker, that not including non-fatal collapses such as in the cases of Child B, Child E and Child F was a "missed opportunity to find the answer to what was happening".

Peter Skelton KC, representing other families in the inquiry, said the deaths had not been investigated, that in many cases the causes of actual death "were not known", and "the possibility that someone was harming children was a real one".

Ms Powell replied: "I did, yes. But I didn't feel that there was anyone that fit that bill at that time."

Mr Skelton asked: "Were you expecting a particular presentation or demeanour from a potential murderer?"

Ms Powell replied: "I just don't expect people to behave that way."

Mr Skelton added: "Of course not. Hardly anyone does. But that's the whole point of the [Beverley] Allitt recommendation, is to think that somebody might do and to identify that person in circumstances where the other possible factors have been excluded."

He went on: "You were certainly not in a position to rule out Lucy Letby's involvement in that murder, were you?"

Ms Powell: "No."

Mr Skelton: "And the fact is that you didn't actually, asa manager, need to take a position, did you? You could have simply said, "This is an extremely serious allegation. My babies, who I am responsible for as a manager and a nurse, may have been harmed. I need to ensure that they are – they and their families get the answers they need and as importantly I need to ensure that all babies coming onto this unit are safe."

Ms Powell replied: "Yes."

Mr Skelton added: "That was your responsibility and if you could not exclude the possibility that they were murdered then you failed in that responsibility, didn't you?"

Ms Powell replied: "Yes."

Mr Skelton continued: " I appreciate that you are not alone in this, Ms Powell, and that matters were escalated above you to your nursing director and further up into the medical director and the chief executive, and that steps were not taken immediately to intervene.

"But you recognise now that if professionals, when the professionals raise suspicions that couldn't be excluded and that were not obviously malicious, that the police needed to be called?"

Ms Powell replied: "Yes."

Mr Skelton concluded: "And that should have happened as soon as those suspicions were articulated; is that right?"

Becoming tearful, Ms Powell replied: "Yes."

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 is expected to sit until early 2025, with findings published by late autumn of that year.