What Datix is and how it works in NHS Trusts
Datix is the mandatory patient-safety incident-reporting software used across the NHS. Every serious adverse event, near-miss, equipment failure, medication error, infection incident, staffing concern or facility problem should be logged on Datix by the staff member who encounters it. The system is used for clinical governance, regulatory reporting to the Care Quality Commission, serious incident reviews, and the Trust’s own risk registers.
A complete Datix record for any given clinical period therefore provides a contemporaneous, documentary picture of the hazards and failure modes on the ward in question. It is the opposite of retrospective reconstruction — it is the Trust’s own system, logging events in real time as experienced by the staff on the ground.
For the Countess of Chester neonatal unit in 2015–2016, the Datix record has been partially examined at the Thirlwall Inquiry, where extracts have been put to witnesses. What those extracts show is a picture significantly at odds with the prosecution’s narrative that the only operative cause of the elevated mortality was the deliberate actions of one nurse.
What the COCH 2015-16 record actually shows
The portions of the Datix record that have entered the public domain through the Thirlwall Inquiry hearings include entries across several categories:
- Environmental failures — including the sewage and plumbing incidents described in detail below.
- Equipment failures — including monitoring-equipment calibration and infusion-pump faults.
- Staffing gaps — including senior nurse and consultant-rota gaps at critical periods within the indictment window.
- Pharmacy and medication entries — including TPN dispensing issues.
- Transfer and acuity entries — including records of infants admitted whose acuity exceeded the unit’s Level 2 designation.
The prosecution did not use the Datix record as an exhibit. The defence had limited access to the full record before trial. The jury was therefore not in a position to weigh the contemporaneous documentary picture of the unit against the prosecution’s single-cause hypothesis.
Sewage, plumbing and equipment-failure entries
Among the most significant environmental entries in the 2015–16 Datix record are those relating to sewage and plumbing failures on and adjacent to the neonatal unit.
A sewage back-up incident is documented in the record. Raw sewage backing up into or adjacent to a neonatal intensive care environment is a serious infection-control event. Neonates — particularly extremely preterm neonates — are profoundly immunocompromised. The pathogen load associated with a sewage event includes organisms capable of causing the sepsis, bowel compromise and sudden deterioration events that occurred during the indictment period. The prosecution did not engage with this incident in its evidence.
Plumbing entries in the record document water-system problems in the same building period. NHS guidance on water safety in clinical environments — specifically in relation to Pseudomonas aeruginosa and Legionella risk in neonatal units — identifies water-system integrity as a patient-safety issue. The Countess of Chester water system in this period was the subject of Trust-level attention that is now partially visible through Thirlwall evidence bundles.
Equipment-failure entries include monitoring-device faults and infusion-pump calibration issues logged during the indictment window. These are precisely the categories of equipment failure that clinicians rely on to detect and respond to neonatal deteriorations — meaning equipment failures in this category directly affect the timeliness and effectiveness of clinical response to deteriorating infants.
Staffing-gap and consultant-rota entries
The Datix record also shows staffing-gap entries during the indictment period. These include:
- Senior nurse and band-6 charge nurse coverage gaps — periods where the unit was running below minimum safe-staffing thresholds as defined by NHS workforce guidance for neonatal units.
- Consultant-rota gaps — periods where senior medical cover for the neonatal unit was reduced, with registrar-level cover substituted. For a Level 2 unit treating infants of Level 3 acuity, reduced consultant presence means reduced capacity to escalate and respond to complex deteriorations.
- Out-of-hours cover patterns — the staffing-gap entries are not randomly distributed across the clock. They are concentrated in patterns consistent with the highest-risk out-of-hours periods on a neonatal unit.
The RCPCH 2016 review of the unit, commissioned by Trust executives, itself noted staffing and rota concerns. Those concerns were live and documented in the Datix system throughout the indictment period — not as retrospective reconstruction, but as contemporaneous staff reports.
Why the jury did not see the full Datix record
The Crown’s case did not require the Datix record and did not exhibit it. The prosecution’s theory — that the cluster was caused by deliberate acts — was not advanced through a comparative analysis of what the Datix record showed versus what a natural-cluster record for an equivalent unit would look like. The single-cause hypothesis did not need to engage with the unit context because it attributed the causation to an individual rather than to the environment.
The defence had access to some Datix material but the evidence suggests the full record was not systematically disclosed or exhibited. Witnesses at the Thirlwall Inquiry have described the incomplete picture available to investigators and clinicians at the time of the prosecution.
Post-conviction, the Hummingbird whistleblower report (December 2025) described the Cheshire Police investigation as having adopted a suspect-first scoping decision that meant unit-level environmental and systemic factors were not investigated in parallel with the individual-suspect hypothesis. The Datix record — as the primary contemporaneous documentary record of those unit-level factors — was therefore neither fully obtained nor presented to the jury.
What it means for the natural-cause framework
The Shoo Lee Panel, in its case-by-case review, concluded that every deterioration across the indicted cases was explicable by natural causes or identifiable clinical error. The Datix record is the institutional documentary underpinning of that conclusion: it shows in real time that the unit was experiencing exactly the categories of environmental, equipment and staffing failure that would predict a cluster of serious neonatal deteriorations independently of any individual nurse’s conduct.
A natural-cause framework for the cluster does not require mystery or coincidence. It requires only that the jury be shown the full contemporaneous picture of the unit’s condition — the picture that the Datix record documents. That picture was not shown to the jury. The CCRC review, operating on the basis of primary records, is in a position to examine it.