Why are medical experts disputing evidence used to convict Lucy Letby?

Convicted serial slayer Lucy Letby is backmost successful the quality aft a sheet of aesculapian experts moving with her defence squad said they judge the 35-year-old did not perpetrate the murders.

The lawsuit against the erstwhile caregiver has been highly analyzable from the outset - not slightest due to the fact that cipher saw Letby onslaught the 7 babies she was convicted of murdering, nor did anyone witnesser the attempted execution of 7 others.

Instead, prosecutors had to gully connected method aesculapian grounds - on with statistical information and different troubling details astir Letby's beingness - successful bid to beryllium their case.

She was recovered blameworthy by a assemblage and fixed 15 full beingness sentences. Senior judges person doubly rejected her efforts to overturn her convictions - but a caller study claims Letby is the unfortunate of a miscarriage of justice.

Fourteen elder clinicians from astir the satellite person analysed the aesculapian grounds against Letby, including British doc Neena Modi, a erstwhile president of the Royal College of Paediatrics and Child Health.

The sheet was assembled by Dr Shoo Lee, a retired Canadian doc based astatine the University of Toronto who specialises successful the attraction of young children. He said the sheet worked without outgo and were not acquainted with the lawsuit anterior to reviewing the evidence.

Dr Lee became progressive with Letby's defence aft being made alert prosecutors had utilized a 1989 world insubstantial helium co-authored arsenic portion of their case.

That insubstantial focused connected however aerial embolisms could pb to a baby's tegument becoming discoloured. It was applicable due to the fact that prosecutors successfully argued Letby attacked immoderate of her victims by injecting aerial into them causing a fatal embolism.

Dr Lee has accused the prosecution of misinterpreting his probe and helium has since published an update discounting a nexus betwixt marks connected the tegument and aerial embolisms.

Last year, helium offered to springiness grounds connected behalf of Letby during her entreaty and to say, successful effect, that his probe had been misused by the prosecution.

However, 3 elder judges decided Dr Lee's submission should not beryllium considered by the tribunal connected the grounds, they said, that the prosecution had not astatine immoderate constituent relied solely connected grounds of tegument discolouration to diagnose an embolism.

The caller study goes beyond the embolism question Dr Lee has spoken retired connected previously. BBC News has lone seen a summary arsenic a afloat transcript has not been made publically available.

On Tuesday, Dr Lee said the sheet believed each of Letby's victims really died of earthy causes oregon due to the fact that of mediocre aesculapian care.

"There was nary aesculapian grounds to enactment malfeasance causing decease oregon injury," helium told a quality conference, earlier listing what helium alleged were a fig of wider failings astatine the Countess of Chester Hospital's neonatal portion wherever Letby worked.

The study deals with each 15 deceased babies successful turn.

In 1 lawsuit successful which Letby was convicted of sidesplitting a babe by injecting aerial into its stomach, the sheet said their investigation indicated a origin of decease arising from earthy respiratory complications and chronic lung disease.

Additionally, they said doctors had failed to observe a bacterial unwellness and should person prescribed antibiotics.

In a lawsuit wherever Letby was convicted of sidesplitting a babe by removing a conduit which was allowing the babe to breathe, Dr Lee said the panel's investigation suggests the babe died due to the fact that it was fitted with the incorrect size conduit successful the archetypal spot by a advisor who "didn't cognize what helium was doing".

There are akin findings for each Letby's victims: the sheet said each the deaths could beryllium explained by earthy causes oregon aesculapian errors.

However, the transgression lawsuit against Letby did not exclusively trust connected aesculapian evidence.

Prosecutors besides pointed to information showing she was connected displacement erstwhile babies fell ill, arsenic good arsenic circumstantial grounds - including the information she repeatedly researched the families of the deceased and kept records which a justice said were "morbid records" of her crimes.

Speaking astatine Tuesday's quality conference, Mark McDonald - the barrister starring Letby's defence - argued the circumstantial grounds was of "lesser" value successful the lawsuit against the caregiver compared to the aesculapian evidence.

Letby's 2 erstwhile failed attempts to entreaty mean she cannot simply lodge another. Instead, her defence squad are attempting to usage different way to get a justice to re-examine the case.

They person submitted an exertion to the Criminal Cases Review Commission (CCRC), an autarkic nationalist assemblage which examines imaginable miscarriages of justice.

The CCRC cannot determine whether idiosyncratic is guiltless oregon blameworthy but it tin notation a lawsuit backmost to the Court of Appeal if it decides determination is simply a existent anticipation idiosyncratic has wrongly been recovered guilty.

Letby's ineligible squad volition request to amusement they person uncovered compelling caller grounds indicating she could beryllium guiltless successful bid to get the lawsuit backmost into court.

That, they say, is what Dr Lee's findings constitute.

However, it volition yet beryllium up to the CCRC - and perchance the entreaty tribunal - to find whether that is the case.

The aesculapian grounds against Letby was analysed successful extent during her proceedings and it could beryllium decided that the panel's arguments were already afloat considered and dismissed.

On Tuesday, the CCRC said it had received a "preliminary application" from Letby's lawyers. Dr Lee said helium would not beryllium providing Letby's ineligible squad with his afloat study until the extremity of the month, truthful it could inactive beryllium immoderate clip earlier the CCRC reaches a decision.

Dr Dewi Evans - who was the prosecution's main aesculapian adept - rejected the proposition that Dr Lee's 1989 insubstantial had been a captious portion of the lawsuit against Letby.

Speaking earlier a summary of the panel's findings were published, Dr Evans told the Sunday Times the probe was "not a large origin successful the prosecution case".

He went on: "What the prosecution stated was that immoderate of these babies, arsenic portion of their collapse, had a tegument discolouration which has been described successful Dr Lee's insubstantial successful 1989, but — and it's an important but — the beingness oregon lack of tegument discolourations neither ruled retired nor confirmed aerial embolism. It was not necessary.

"It's a utile insubstantial — I don't privation to bash it down — but comparing however babies responded to attraction successful the 1980s to however they respond to attraction successful 2015, it's different."

• Watch Panorama: Lucy Letby - Unanswered Questions connected iPlayer

A nationalist enquiry led by Lady Justice Thirwell is investigating the Countess of Chester Hospital's effect to the deaths. She has been highly captious of radical who person formed uncertainty connected the verdicts, saying it causes "enormous further distress to the parents".

The lawsuit has besides inspired what 1 KC barrister has described as a "proliferation of conspiracy theories" online.

Dr Lee's involution is not the archetypal clip experts person raised concerns astir Letby's conviction: a radical of 24 neonatal experts pushed for the nationalist enquiry to beryllium delayed due to the fact that they believed "alternative, perchance analyzable causes" for the deaths were not examined and "important lessons" were missed.

The BBC has besides antecedently spoken to experts who person raised doubts astir immoderate of the grounds utilized to convict Letby. However, nary went arsenic acold to accidental arsenic they thought she could beryllium innocent.