The inquiry has closed for the day and we're ending our live coverage. Here's some key takeaways from throughout the day.

• An e-mail from a nursing boss sent in May 2016 spoke of concern at a possible "staff trend" in deaths on the neonatal unit and said the issue was "potentially very serious"
• The following month, the deaths of two out of three triplet brothers "catapulted" Letby and neonatal mortality to the top of the executive team's agenda
• After the second brother's death, a neonatal consultant asked a senior nurse to remove Letby from the ward, but this was not done
• Concerns had been raised following a cluster of deaths from mid-2015, but a serious incident panel that July concluded "no further investigation [was] warranted"
• Notes suggested that a lawyer for the hospital advised its medical director to contact the police in June 2016, almost a year before they were in fact contacted
• In July 2016, Letby was moved to non-clinical duties, but in the following months opened a grievance process against the hospital trust
• Having been told she could return to the neonatal unit, in January 2017 she e-mailed all staff incorrectly claiming that she had been "fully exonerated" following an investigation

• Lady Thirlwall, who is leading the inquiry, said "noise" surrounding the case had caused "enormous additional distress" to the parents of the babies

Judith Moritz
Reporting from the inquiry

We've just heard that Rachel Langdale KC, counsel to the inquiry, has finished up for today - a little earlier than scheduled.

The inquiry has risen early too. It will convene again tomorrow at 10:00 BST.

Judith Moritz
Reporting from the inquiry

On 5 April 2017, Letby was informed her return to the neonatal unit was to be paused, and it was recommended that she cease to visit the unit, Langdale tells the inquiry.

"It appears that Letby had visited... unsupervised on one occasion in the last week of February 2017 with the knowledge of at least Alison Kelly, Susan Hodkinson, and Karen Rees."

"Letby attended a 'tea party' on the unit with Nurse Z, which Yvonne Griffiths, deputy unit manager, explained to staff was to welcome Letby back onto the unit."

Langdale tells the inquiry that nursery nurse Jean Peers described the event as follows in her evidence: “I was on [at] the weekend and so was Yvonne Griffiths, she said that Letby was coming with Nurse Z and that we would do a tea party to welcome her.

"We did cakes and tea, and she came in and we were all talking, and she did not say a word to us. Yvonne and I were talking a lot to make it nice and relaxed and when she went, we both said, 'oh my God, she is going to make it hard for us when she returns as she seems angry'."

Ms Langdale is discussing the grievance Letby brought after concerns were raised about her.

In January 2017, she says Letby emailed all staff on the neonatal unit stating: “I was redeployed from the unit in July 2016 following serious and distressing allegations of a personal and professional nature made by some members of the medical team.

“After a thorough investigation it was established that all the allegations were unfounded and untrue and I have therefore been fully exonerated.

"I have received a full apology from the trust... I will begin making my return to the unit in the coming weeks.”

Hospital management were aware of the email, the inquiry hears.

However, Ms Langdale says: “The inquiry has not seen any evidence to suggest that anyone at the hospital responded to Letby’s email to correct her and to clarify that she had in fact not been investigated at all, let alone exonerated.”

Jonny Humphries
Reporting from the inquiry

Langdale says it was only the “tenacious lobbying” of senior consultants on the neonatal unit that prevented Letby from being returned to her usual duties.

Langdale says the fact Letby was excluded from that unit “may have been, to some degree, chance”.

She says the initial plan was that Letby would return in January 2017 under supervision, but this was only abandoned due to staffing pressures.

Langdale says: “Later that year it was being communicated that she would be returning to the ward, despite the fact that the investigations were ongoing.

“Her planned return to the ward on 3 April 2017 only appears to have been stopped because of the tenacious lobbying of the consultants.

“But for their determined approach, it appears likely that she would have been permitted to return to dealing with babies.”

Judith Moritz
Reporting from the inquiry

The inquiry is told that on 2 May 2017, hospital chief executive Tony Chambers wrote to Cheshire Police Chief Constable Simon Byrne to say: “I am writing formally requesting Cheshire Police conduct a forensic investigation into the circumstances surrounding the deaths with a view to excluding any unnatural causes.”

Three days later the first meeting of Operation Hummingbird (the name given to the police investigation) took place.

Langdale says: “The police were not contacted until May 2017. In that time, Letby worked without formal restriction on her registration from her regulator, the Nursing and Midwifery Council.

"Whilst she was eventually removed from a patient-facing role, whether and if so how she was able to obtain any placement elsewhere or to visit the neonatal unit at the hospital will be explored in oral evidence."

Judith Moritz
Reporting from the inquiry

On 5 April 2017, there was another meeting between Letby and managers, including the director of nursing Alison Kelly, at which Letby was told her return to the neonatal unit was to be paused and reviewed after Easter.

Langdale says that also discussed were "visits" Letby had been making to the neonatal unit.

"[Letby] was advised that these should also be paused. This appears to be a reference to the fact that, prior to this date, Letby had been attending the neonatal unit," she says.

"Whether and how often this occurred and, if it did, who sanctioned it, are matters the inquiry will be investigating."

Judith Moritz
Reporting from the inquiry

On 3 April 2017, there was a discussion between hospital executives about calling the police, but it didn’t happen for another month.

One executive - Stephen Cross, director for corporate and legal services - created a document which included the line: “In our view, there is no evidence to justify a criminal investigation.”

Langdale says the inquiry will look "at the content of this document in greater detail during the hearing, in terms of what it may reveal about the thinking of the executive directors at this time.”

Judith Moritz
Reporting from the inquiry

The inquiry is now hearing about another meeting, held in February 2017, between hospital executives, Letby and her parents.

During the meeting, Letby was told that the hospital consultants would be sending her a written apology.

Langdale KC says: “In the course of the meeting, Letby’s father is recorded as suggesting that the consultants had 'got away with calling my daughter a murderer'."

In response Mr Chambers is recorded as saying: “Trust me, they haven’t. Ian [Harvey] and I have drawn the line, a different conversation will come next.”

Judith Moritz
Reporting from the inquiry

The inquiry hears that, at the end of January 2017, Letby told director of nursing Alison Kelly she had been speaking to a colleague - referred to as Dr U - at Alder Hey Children’s Hospital in Liverpool about the possibility of an observational placement.

Observational placements allow healthcare professionals to spend time observing others in order to build up their knowledge.

Langdale says that, at the time, Dr U knew the mortality rate on the Countess of Chester’s neonatal unit was being investigated, that Letby had been identified as a common factor in the deaths, and that she had been moved to non-clinical duties.

Dr U reported in his witness statement that Letby attended Alder Hey for a number of supervised visits - observing outpatient work, clinics, ward rounds, and team meetings - but that, to his knowledge, she had “no unsupervised patient contact”.

“Letby attending Alder Hey Children’s Hospital in any capacity during the period she was excluded from the neonatal unit is an area of particular concern for the inquiry,” Langdale says.

She adds it was not until June 2017 that Letby was told she could no longer go to Alder Hey, and that the extent to which Alder Hey were informed about the concerns surrounding Letby needs “to be clearly understood”.

Judith Moritz
Reporting from the inquiry

Tony Chambers, the then chief executive of the NHS trust, is recorded in an extraordinary meeting of the hospital board in January 2017 as saying Letby’s grievance procedure “exonerates her”.

Counsel to the Inquiry Rachel Langdale KC says “Mr Chambers appears to have told the board that the concerns about Letby were not true and that the grievance process exonerated Letby.”

Following this meeting, Chambers met with Letby and told her that the board was “absolutely clear” in its support for her, and that the consultants had been told to apologise to her.

The inquiry hears that claims Letby had been exonerated at this stage were “not confined to a single meeting”.

Chambers has told the inquiry, in his witness statement, that he wouldn’t have said she was exonerated.

Langdale now says “the minutes of the board meeting the day before record Chambers using exactly this word about the grievance process.”

The inquiry will examine the board's actions and what happened at this meeting.

Jonny Humphries
Reporting from the inquiry

We have been hearing about Letby's time away from the neonatal unit - on the risk and safety team - during which time she was provided regular support meetings.

Despite the concerns, Letby was told discussions were under way about returning her to her normal duties.

A letter to Letby following one of her support meetings stated: “Karen [Rees] (head of nursing for the urgent care division) advised that she was keen to create a supportive environment for you to return to the unit and that she was working with you in planning for returning to the unit in early January 2017.”

Langdale says: “The inquiry will be investigating why it was, before all of the external investigations were completed, the decision had apparently been made to permit Letby to return to the neonatal unit.”

Jonny Humphries
Reporting from the inquiry

In July 2016, management at the Countess of Chester decided against returning Letby to the neonatal ward in the short-term.

HR director Sue Hodkinson wrote a note following an executive meeting about the issue, which states: “pressures on unit/cannot guarantee 1-1 supervision.”

Letby was then transferred to the risk and safety team, which was not patient-facing and involved dealing with complaints.

Langdale says this was a temporary measure and in September 2016 the issue of where Letby was to work was raised.

She says Karen Rees, head of nursing for the urgent care division, wrote to Alison Kelly - at that time a senior manager - describing the delay in transferring Letby back to the neonatal unit as “wrong and immoral”.

Rees went on to suggest concerns about Letby were based on “a senior clinician having a ‘gut feeling’ with no evidence,” adding: “This allegation is massive and if this clinician and anyone is of this belief, then why have the police not been called.”

Judith Moritz
Reporting from the inquiry

Letby raised a grievance procedure with the hospital in response to being taken off the unit, the inquiry hears.

Langdale says Letby's mother accompanied her to a meeting with senior executives in December 2016 and read out a statement.

She adds there is "evidence which may suggest that the grievance came to dominate the thinking" of executive directors and that, once completed, the grievance process was viewed as having “exonerated” Letby when, in fact, it contained no investigation into her actions whatsoever.

"We will be examining this issue with care. The use of a grievance process as a means to avoid scrutiny is something that the system must be capable of recognising and preventing,” she says.

Ian Harvey, the former Countess of Chester Hospital medical director, has told the inquiry that when it came to communications with the parents of the babies who died or collapsed “in short, I think we got this wrong.

"Families were let down and the communications we had with them should have been better... families did not receive the support they should have.”

Rachel Langdale KC says “the Inquiry will be exploring this with Mr Harvey and others.”

Judith Moritz
Reporting from the inquiry

There were also several external reviews happening at this time, including one by the Royal College of Paediatrics and Child Health, and another by an external neonatologist - Dr Jane Hawdon - who the hospital invited to review the deaths.

She was provided with case notes for 13 deaths and four “near misses”. The police had still not been called.

Rachel Langdale KC says: “In relation to Dr Hawdon’s report, we will be looking at the decision to send it to families of those babies Letby attacked. This occurred on 28 April 2017.

"Dr Hawdon’s report does not, on its face, appear to have been written for the benefit of a non-medical audience. It consists of annotations and technical language which is unexplained,” Langdale explains.

Dr Hawdon has told the inquiry that she believes the families should have been shown her findings at a face-to-face meeting, rather than sent out without a covering note or explanation.

She has told the inquiry: “It is my personal opinion that the case review reports alone would have been difficult for families to understand and could have added to confusion and grief.”

Langdale says the matter is considered to be "of a high degree of importance".

Judith Moritz
Reporting from the inquiry

There were a range of internal reviews ongoing as Letby was taken off the neonatal unit in July 2016 and moved into a back-office job in the hospital’s ‘Risk and Patient Safety’ office.

Langdale says an "extraordinary meeting of the board of directors of the Trust" took place on 14 July 2016.

She adds "a range of internal reviews were ongoing, but in November 2016 Letby was told that she would be allowed to return to the unit.

“The inquiry will be investigating why it was, before all of the external investigations were completed, the decision had apparently been made to permit Letby to return to the neonatal unit.”

Jonny Humphries
Reporting from the inquiry

The inquiry is hearing that there are records suggesting that medical director Ian Harvey was advised to contact the police in June 2016.

Langdale says that on 29 June that year, Harvey held a meeting with Stephen Cross, the director of corporate and legal services at the Countess of Chester hospital trust, about the situation on the neonatal ward.

A contemporaneous note of that meeting written by Mr Cross states: “ADVICE ‘Police’ need to be involved now.

"Death of triplets has raised concern. Nurse was on duty at deaths. Sufficient level of concern that illegal activity in neonatal.”

Langdale says Harvey has stated he was “unable to recall the meeting”, and in his statement to the inquiry he added that he “does not remember anyone giving him advice at that point that the police should be contacted”.

At about the same time, Harvey was also copied into an email chain involving the senior consultants in which it was suggested that the police should be called in.

Langdale states: “The Cheshire Police were not, in fact, contacted by the Trust until nearly one year later in April 2017.”

Jonny Humphries
Reporting from the inquiry

The focus now turns to an email from Dr Stephen Brearey to hospital executives sent on 28 June 2016.

Ms Langdale said that despite the concerns of consultants on the unit, and the unexpected deaths of Child O and Child P, senior staff appeared to be willing to allow Letby to carry on working day shifts.

Dr Brearey's e-mail referred to the "sudden deterioration of apparently well babies with no cause identified" and the "presence of one member of nursing staff at these episodes".

He wrote that there had been a "watchful, waiting approach" to the situation since a meeting with medical director Ian Harvey and director of nursing Alison Kelly in March.

"However, since the episodes and deaths last week there was a consensus at the senior paediatricians' meeting that we felt that on the basis of ensuring patient safety on [the neonatal unit] this member of staff should not have any further patient contact on [the unit]," he wrote.

Away from the actual inquiry now for a moment, we have been hearing from a lawyer representing three families who suggests that the NHS duty of candour may need to be "reframed or strengthened" in response to the Lucy Letby case.

Speaking on BBC Radio 4's World at One programme on Tuesday, the lawyer Richard Scorer also dismisses the idea that the inquiry's terms of reference should be changed to include the possibility that some of the babies might have died from alternative causes - as was suggested by some scientists in a letter last month.

Scorer says: "The legal position here is absolutely clear. Lucy Letby has been convicted in two trials - one of which lasted 10 months.

"Those convictions were taken to the Court of Appeal and her appeal was rejected. And I urge people actually to read that Court of Appeal judgement. It's available publicly online.

"People can read it and see the reality of what we're dealing with here. I don't accept that the terms of reference should be changed, I don't think that would appropriate," Scorer says.