What the inquiry was set up to do
The Thirlwall Inquiry was established by the Secretary of State for Health and Social Care in May 2024, chaired by Lady Justice Thirlwall. Its remit was to examine the circumstances at the Countess of Chester Hospital’s neonatal unit during 2015–2016 — specifically the governance structures, escalation mechanisms, and institutional responses to consultant and nursing concerns about unexplained deteriorations and deaths among neonates in that period.
The inquiry’s terms of reference were expressly limited to institutional and regulatory matters. They did not permit re-examination of the evidence presented at the criminal trial, assessment of whether the convictions were safe, or any finding that would bear directly on the legal questions now before the CCRC. This was not an oversight — it was a deliberate boundary set at the outset to avoid the inquiry prejudicing or interfering with parallel legal processes. Lady Justice Thirlwall acknowledged this limitation repeatedly during evidence hearings.
What the report found
On board governance, the report found that the Countess of Chester Hospital’s Board did not receive any reports about the deaths of babies and children at any stage during the period under examination — only adult deaths were reported to it. “This was a serious failure of governance, which no one on the Board seems to have noticed,” the report says, finding that the structure had “removed the voice of children and babies from the Board” (Summary report, paragraph 3.9).
On executive responses, the report found that senior managers acted too slowly and were poorly coordinated once consultant paediatrician concerns were raised. The Royal College of Paediatrics and Child Health (RCPCH) review commissioned by hospital leadership “could not and did not address the doctors’ concerns and should never have been undertaken” (Inquiry press release, 15 September 2026). Rather than being believed, the consultants who raised concerns were themselves investigated under Letby’s grievance process; three were told to apologise to her. “The consultants were to be forced to apologise when they had nothing to apologise for, and were required to mediate. The way the grievance and its consequences were handled was deplorable” (Summary report, paragraph 3.134). The report also found “senior nurses never accepted that the consultants’ concerns were – or might be – justified”, and a “prolonged delay by senior managers in calling the police” (press release, 15 September 2026). (The Operation Duet corporate-manslaughter investigation, separately, has produced criminal arrests of three former senior leadership members on 30 June 2025, with one re-arrested on 23 April 2026 for perverting the course of justice — see our April 2026 arrest analysis.)
On regulatory oversight, the report examined the Care Quality Commission’s routine inspection of the Countess in February 2016. The team inspecting neonatal services did not have the hospital’s data on unexpected deaths and was not even aware it existed, so it did not ask about it — “this was a serious failing by CQC” (Summary report, paragraph 3.25). The resulting inspection report, published that June, rated the hospital’s children’s services “good” overall without identifying the rise in neonatal mortality. “It is not easy to see how a regulator can be satisfied about the process in place where, as here, CQC did not know and did not ask about the number of deaths and how they had been investigated and lessons learnt,” the report says (paragraph 3.27).
The report also describes how parents were treated. They were “kept in the dark for years” about the possibility that their babies had been deliberately harmed; their consent was not obtained before their babies’ medical records were shared with external experts; and only in 2018 did some learn that the collapses and deaths might have resulted from the actions of a nurse in whom they had put their trust. “The lack of consideration shown to the parents at that time was reprehensible,” the Inquiry said on publication (press release, 15 September 2026).
The report sets out 17 recommendations, at chapter 45. They include fitting baby monitors (in-cot cameras with livestreaming video) to every cot and incubator in every neonatal unit, centrally funded and ring-fenced (Recommendation 1); digital devices to restrict and record access to insulin storage, with all neonatal units required to comply by 31 March 2027 (Recommendation 2); the National Bereavement Care Pathway for neonatal death implemented nationally by 31 August 2027 (Recommendation 3); and a one-page Suspicion of Deliberate Harm Protocol for NHS managers (Recommendation 9) — because, as the Inquiry notes, “to this day there is still no NHS-wide protocol on deliberate harm” (press release, 15 September 2026).
Where the carve-out matters
The conviction-safety carve-out is significant because a substantial portion of public and media attention on the inquiry has focused on questions that fall squarely outside its terms of reference: whether the expert evidence at trial was reliable, whether the statistical shift-pattern argument was valid, and whether the insulin assay evidence was correctly interpreted. The inquiry heard no expert evidence on these scientific questions and reached no conclusions about them.
This creates a risk of public misreading now that the report has been published. Findings that institutional failures occurred — that governance was inadequate, that escalation was slow — are institutional conclusions. They do not, in themselves, address whether Lucy Letby committed the acts she was convicted of. Equally, the report’s silence on conviction safety does not constitute an endorsement of the convictions. The two domains are legally and analytically separate.
Supporters of a CCRC referral note that the institutional findings are potentially relevant to the broader picture: governance was poor and escalation was inadequate, so the trajectory of clinical deteriorations and deaths at the unit was being managed within a system with significant structural weaknesses — a context that bears on how natural-cause explanations should be weighed.
How the findings interact with the CCRC review
The CCRC review, confirmed publicly by chair Dame Vera Baird in February 2026, is examining the scientific and evidential basis of the convictions. The Thirlwall report is a separate process — but its findings may become material in at least two indirect ways.
First, the Shoo Lee International Expert Panel, whose February 2025 report assessed the medical evidence case by case, operated as a parallel scientific review with no formal connection to either the inquiry or the CCRC. The Panel’s findings — that natural-cause explanations exist for each incident — are the primary scientific input to the CCRC process. The Thirlwall report neither endorses nor contradicts the Panel; they address different questions.
Second, if the CCRC ultimately refers the case to the Court of Appeal, the court will consider fresh evidence in the round. The institutional picture established by the Thirlwall report may form part of the broader factual context, though its direct evidential weight in a criminal appeal will depend on how the court defines the scope of fresh-evidence review.
What now — and the knock-on effect on the inquests
On 13 May 2026 the HM Coroner relisted the inquests into the deaths of six of the babies Letby was convicted of murdering — the full hearings, originally scheduled for September 2026, will now provisionally begin on 10 May 2027. The coroner cited the need for the Thirlwall Inquiry’s findings to be fully considered before the inquests proceed. See our inquests-delayed-to-2027 analysis. The 2026 timetable of converging formal-record processes — Thirlwall report, inquests, CCRC pathway — will instead unfold sequentially across 2026 and 2027.
Now that the report has been published, the conviction-safety question remains entirely with the CCRC. The Thirlwall report does not accelerate or constrain that process, but it closes the inquiry phase of the institutional examination of the Countess of Chester Hospital. Government has committed to responding to the 17 recommendations within a defined period.