Lucy Letby, Britain’s worst child serial killer, has formally lodged a bid to challenge her convictions at the court of appeal, officials have confirmed. Court staff said on Friday they had received an application for permission to appeal against all of the nurse’s convictions. Last month, Letby was sentenced to a rare whole-life order after jurors convicted her of the murders of seven babies and the attempted murders of six others at the Countess of Chester hospital’s neonatal unit in 2015 and 2016. Typically, applications for permission to appeal against a crown court decision are considered by a judge without a hearing. If this is refused, people have the right to renew their bid for permission at a full court hearing before two or three judges. The 33-year-old became only the third woman alive to be handed a whole-life jail term. The other two women serving whole-life terms are Rose West, who tortured and killed at least nine young women in the 1970s and 80s, and Joanna Dennehy, who murdered three men in what came to be known as the Peterborough ditch murders in 2013. Letby refused to leave the court cells as the parents of her newborn victims described the horrifying impact of her crimes during the trial at Manchester crown court. The Crown Prosecution Service has said there will be a hearing at Manchester crown court on 25 September on whether it intends to bring a fresh trial against Letby in relation to several outstanding attempted murder charges. The jury failed to reach a verdict on six counts of attempted murder last month. The CPS said the hearing would determine whether to pursue a retrial in relation to the outstanding counts. According to CPS guidance, the decision to seek a retrial will depend on the public interest. The guidance states that “only cases involving significant public interest factors in favour of prosecution warrant a retrial”. Elsewhere, the Guardian reported on Friday that the health service ombudsman said the upcoming public inquiry into the nurse’s crimes must be widened to examine the NHS’s “cover-up culture” over failures in patient safety. Rob Behrens said the full statutory inquiry should also look into why so many hospital bosses ignored concerns about lapses in safety and victimised whistleblowers who raised them. While the inquiry’s first duty was to give the families of Lucy Letby’s victims the answers they wanted, it should also explore how other hospitals had demonstrated the same “cover-up culture and dismissive attitude” that consultant paediatricians experienced at the Chester hospital, Behrens said. “We need the inquiry to thoroughly examine NHS leadership, accountability and culture to contextualise what happened. “Among the many questions the inquiry will need to answer, and without prejudice, is why did the leaders of this trust act in the way they did? And, related to that, why do leaders in the wider NHS too often act in a way that prioritises protecting the reputation of their organisation over patient safety?” A Department of Health and Social Care source said the inquiry’s terms of reference are still being drawn up by the judge and families and it could not prejudge them.