Why it matters in the Letby case
Subsequent analysis has examined the scope of Hummingbird, its relationship to the separate Operation Duet, and the December 2025 Hummingbird whistleblower report.
Institutional explainer
Operation Hummingbird — investigation timeline
Operation Hummingbird is Cheshire Police's investigation into the deaths and collapses on the unit. The investigation timeline and scope decisions are part of the public record.
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Prosecution position
Operation Hummingbird produced the charges on which two juries convicted, and the convictions were upheld on direct appeal in 2024.
Expert challenge / post-conviction reading
Cheshire Police opened Hummingbird in May 2017, and the scoping decisions taken in its first weeks determined what it looked for and whom it instructed as experts. In December 2025 an anonymous whistleblower released a 150-page report, hosted at lucyletby.org, on the investigation's genesis and the 2017 information flows between Trust and police.
What remains uncertain
The whistleblower report is anonymous and unverified; the site records what it says and its status, not more. Hummingbird is also routinely confused with Operation Duet, which asks a different question entirely.
Common questions
When did Operation Hummingbird begin?
May 2017, following the Trust's referral.
What is Operation Duet?
A separate Cheshire Police operation connected to the same unit. Public coverage often treats 'the Letby investigation' as one thing; it is two, asking different questions. See the linked explainer.
What is the Hummingbird whistleblower report?
A 150-page anonymous report released in December 2025, hosted at lucyletby.org, notable for its specificity on the investigation's genesis and on information flows between the Trust and the police in 2017.
Has the report been verified?
No. It is anonymous and its claims are not independently confirmed. The site records its existence and content, not its accuracy.
Related reading
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