The Thirlwall Inquiry has heard evidence from Dr Gibbs, a treating paediatrician at the Countess of Chester Hospital from 1994 and in post in 2015, when Letby worked as a neonatal nurse.

Dr Gibbs described how tensions escalated between consultants and nurses as a series of unexpected baby collapses and deaths occurred. He admitted feeling responsible, along with others, for not bypassing hospital management in 2015 when serious concerns were raised with the hospital's executive directors.

He revealed to the Inquiry that he had sent emails highlighting three deaths—referred to as Babies A, C, and D—and mentioned informal discussions where Lucy Letby’s involvement in these cases, as well as in the unexplained collapse of Baby B, was noted.

Dr Gibbs also described it as a "serious failing" that the medical team did not follow up on the unusually high insulin levels in Child  F and Child L until two years later. He admitted that he and his colleagues, including more experienced trainee paediatricians, failed to recognise and act when insulin was used to harm babies in the unit. In the cases of Child F and Child L, the blood insulin and c-peptide results displayed on the patient result system and in printed copies sent direct to the unit, did not specify that the result suggested the administration of insulin or that it was likely exogenous (synthetic and administered). A screenshot of Child F’s results, visible only on laboratory computers, suggested exogenous insulin, but it is unclear if this was communicated to the unit staff.

At first, no one suspected Letby of wrongdoing. However, by February 2016, an internal mortality review raised serious concerns, as it revealed that Letby had been present during many of the critical incidents.

Dr Gibbs explained his efforts to alert senior officials and executive directors about his suspicions but lamented that no action was taken in time to prevent further tragedies. He also suggested that clearer warnings on the results could have raised concerns about potential deliberate harm and aided in managing the cases much sooner.

He acknowledged that the parents involved are likely seeking more than just belated apologies—they want clear explanations of how these devastating events occurred. 

Tamlin Bolton , senior associate solicitor representing a large proportion of the families involved in the Inquiry comments:

“The families I represent are devastated by what has happened to their children and have waited years for answers. The evidence presented by Dr Gibbs highlights the systemic failures that allowed these tragedies to unfold. While the families appreciate the sincerity shown by medical professionals during the Inquiry, what they seek most is a full and transparent explanation of how these events were allowed to happen, and what could have been done differently. They want to ensure that no other families endure the same unimaginable pain and loss.”