July 2026: Government declines to widen the Thirlwall terms of reference (16 July) · new 100-page insulin report to the CCRC challenging the trial evidence (9 July) · Thirlwall report still expected no earlier than September · inquests relisted to 2027 · Shoo Lee Panel: no medical evidence of deliberate harm.
Medical explainer
Total parenteral nutrition (TPN) is intravenous feeding used when a baby cannot tolerate gut feeds. TPN solutions are prepared in a pharmacy and run through indwelling vascular catheters.
TPN was alleged by the prosecution as a route of administration for harmful agents in some Letby counts. Post-conviction expert commentary has addressed the practical pharmacy and clinical workflow constraints on the alleged mechanisms.
The Crown's theory for the insulin counts required that Letby had contaminated TPN stock kept in the ward fridge, from which the affected babies were then fed intravenously.
No TPN bags were retained or tested, so there is no physical evidence of contamination. Independent commentary has also addressed whether the reported insulin value is consistent with a small-volume spike into a slow-running bag, and notes that the ward stock was accessible to all nursing staff on the unit.
Because nothing was retained, the contamination theory can be neither confirmed nor excluded by physical evidence. What remains is an argument about physiological plausibility and about who had access.
Total parenteral nutrition — intravenous feeding used when a baby cannot tolerate feeds through the gut. Solutions are prepared in a pharmacy and given through indwelling vascular catheters.
The prosecution's theory for the insulin counts was that insulin had been introduced into TPN stock held on the unit.
No TPN bags were retained or tested, so there is no physical evidence of contamination either way.
Independent commentary notes the ward fridge stock was accessible to all nursing staff on the unit, which bears on how far access narrows the field.
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