Interview With Prof. Jane Hutton On Lucy Letby

Professor Jane Hutton, chair of the Royal Statistical Society's section on statistics and law, describes being recruited by Cheshire Police in March 2018 to conduct an independent statistical analysis, and then being blocked by the CPS, who instructed police not to proceed with her engagement. She explains in detail why the shift-statistics chart shown to the jury is methodologically flawed: it is constructed as a tautology, selecting events on the basis of who was present and then using presence as proof of guilt. She describes the specific statistical errors — failure to account for shift length, exclusion of non-suspicious events, failure to treat twins and triplets as correlated data — and explains why the approach repeats the mistake made in the Sally Clark case. She notes that the Royal Statistical Society submitted a formal critique to both prosecution and defence before trial, which was not acted upon.