Role in the case
Mr Johnson KC led for the Crown at the 2022-2023 trial at Manchester Crown Court and at the 2024 Child K retrial. He delivered the prosecution opening on 10 October 2022 and the Crown’s closing speech (the first day of closings was 19 June 2023, Chester Standard live-blog). He was the Crown’s public face in court throughout both proceedings.
Specific elements of the Crown case relevant to the review
Three Crown-closing rhetorical elements are now part of the post-conviction review discussion:
- The ‘gang of four conspiracy theory’ framing. In closing, Mr Johnson KC invited the jury to reject what he framed as a defence ‘gang of four conspiracy theory’ — referring to the consultant team (Brearey, Jayaram, Gibbs, Harkness). Independent commentators have noted that the defence’s actual position was confirmation bias, not conspiracy; the Crown’s rhetorical framing allowed it to dispose of the confirmation-bias argument without engaging it evidentially. See the gang-of-four-framing evidence entry.
- The air-embolism-diagnostic-criterion argument. Mr Johnson KC presented Dr Dewi Evans’s application of the Lee & Tanswell 1989 paper as diagnostic. Dr Shoo Lee himself has since publicly stated that his paper was misapplied. See the core air-embolism evidence entry.
- The insulin-assay-as-diagnostic argument. Mr Johnson KC presented the Roche Cobas screening immunoassay result as diagnostic of exogenous insulin administration. The May 2025 Joint Expert Witness Insulin Report sets out, in technical detail, why the screening result cannot bear that evidential weight. See the core insulin evidence entry.
Why this biography is on the site
This biography is a reference page. The Crown’s case and its presentation are the primary public record the post-conviction review now engages. Mr Johnson KC is the public face of that case. Identifying him here is not a claim about his conduct — it is a factual reference for readers navigating court transcripts, Chester Standard live-blog records, and the closing-speech rhetorical analysis.
Read alongside
- The ‘gang of four’ framing
- Summing-up critique
- Kate Blackwell KC — junior prosecution counsel
- Simon Medland KC — junior prosecution counsel
- Ben Myers KC — defence leading counsel
- Mr Justice Goss — trial judge
Source
Trial transcripts (2022-2023 R v Letby, 2024 Child K retrial); Chester Standard contemporaneous court coverage (live-blog entries 2022-2024); Crown Prosecution Service counsel records; Bar Council professional listings.
Last verified: 22 April 2026.