The builder of tragic tycoon Mike Lynch’s ill-fated Bayesian superyacht has launched a £400m legal claim against his widow alleging the tragedy destroyed its business.

The Italian Sea Group (TISG) has filed a €456m (£399m) lawsuit in Sicily against Angela Bacares Lynch – a long-time resident of Chelsea who survived the sinking – and is the legal owner of the company that owns the £30m yacht. The firm claims sales collapsed after the vessel capsized off the coast of Sicily during a freak storm in August 2024.

Mr Lynch, one of Britain’s most prominent technology entrepreneurs, died alongside his teenage daughter and five others when the yacht sank. Mrs Bacares Lynch, who lives in a £7m Georgina house on one of Chelsea’s most prominent streets, declined to comment.

According to a report in the Daily Telegraph, TISG argues the sinking was caused by crew negligence, not a design fault, and says it has suffered “ruinous” financial losses, including a complete halt in sales of Perini Navi yachts, the brand that built the Bayesian.

A source close to the Lynch family dismissed the claim as “opportunistic”, pointing to a UK investigation that raised concerns about the yacht’s design and stability. The Marine Accident Investigation Branch previously said the vessel had vulnerabilities unknown to the crew.

The lawsuit also names the yacht’s captain and two crew members, who are under criminal investigation by Italian prosecutors.

Mr Lynch founded Cambridge-based Autonomy, sold to Hewlett-Packard for £7bn in 2011. He died while celebrating his acquittal on US fraud charges. His estate is already facing a separate £1.5bn legal claim from HP.