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April 2026: Thirlwall Inquiry final report due after Easter · CCRC still reviewing 31+ independent expert reports · Shoo Lee Panel (Feb 2025): no medical evidence of deliberate harm.

Lucy Letby Facts

Biography · Defence witness

Lorenzo Mansutti

Plumber employed at the Countess of Chester Hospital during the 2015-2016 indictment period. Called as a defence witness at the 2023 trial to give evidence on specific plumbing and sewage-system failures he witnessed on the neonatal unit — the same infrastructure failures independently documented in the Trust’s own Datix incident record.

Defence witness
Countess of Chester
Infrastructure evidence
Last updated
4 min read

Why his evidence matters for the review

Mansutti’s evidence is unusual in the case: it is documentary, non-expert, contemporaneous, and given by a person with no clinical axe to grind. He was physically present on the unit performing plumbing work during the indictment period. His description of sewage-system failures, waste-water backflow and contamination of clinical spaces documents a set of infrastructure conditions that constitute a live differential for infection-mediated neonatal collapse.

The significance is structural, not case-specific: Mansutti did not claim any particular collapse was infrastructure-mediated. What he did establish is that contemporaneous physical infrastructure failures existed during the indictment period. That fact creates a differential explanation for the cluster of unexpected collapses — a differential the Crown’s narrative did not substantively engage.

What he testified to

  • Specific incidents of sewage backflow on or near the neonatal unit during the indictment period.
  • Waste-water contamination of clinical work spaces.
  • Infrastructure failures consistent with the incidents independently recorded in the Trust’s own Datix system.
  • The physical condition of the unit’s plumbing during the indictment period.

How his evidence applies to the review

The sewage-and-plumbing differential is a live element in the post-conviction review because:

  • Sewage contamination is a plausible transmission vector for neonatal enterovirus and parechovirus outbreaks (see the enterovirus-parechovirus-outbreak evidence entry).
  • Viral testing of the indicted infants appears to have been absent or limited at the Countess of Chester during the indictment period.
  • The Panel’s case-by-case review finds infection a live differential in several indicted cases.
  • The Trust’s own Datix record independently documents infrastructure failure consistent with Mansutti’s trial evidence.

Why this biography is on the site

Most of our biographies are of experts, clinicians, lawyers and campaigners. We include Mr Mansutti’s biography because his evidence is load-bearing on the infrastructure-mediated-infection differential — one of the strongest differential-explanation lines in the post-conviction review — and it is a documentary witness account that the ordinary reader can evaluate without clinical expertise.

Read alongside

Source

Trial transcripts (defence case, 2023); lucyletbyinnocence.com evidence gallery; Countess of Chester Trust Datix incident record (disclosed at Thirlwall Inquiry); science4justice.nl sewage-and-infrastructure commentary.

Last verified: 22 April 2026.