Jonathan joined Edmonds Marshall McMahon in April 2026, with over 35 years’ experience advising on complex professional negligence, fraud and commercial disputes. He is a specialist claimant professional negligence lawyer, with extensive experience acting in both individual and group claims, and has secured successful outcomes for clients at every level of the senior courts, including the Supreme Court, Court of Appeal and High Court, as well as through mediation.
He is known for his calm and measured approach to litigation, combined with deep tactical experience and longstanding relationships across the profession. Jonathan regularly advises on fraud claims, often with an international dimension, and has significant experience in injunctive relief and enforcement matters. He also maintains a broad corporate and commercial practice.
His recent work also includes successfully concluding, following a contested trial, a group claim against a solicitor arising from an unauthorised collective investment scheme connected to the purchase of hotel rooms; acting for an airline in cross-border freezing applications arising from a fraud; and defending a pensions company against a £138 million claim brought by the Pensions Regulator.
Contact Jonathan
Office: 020 7583 8392
Mob : +44 (0)7422 072525
Email: jonathansachs@emmlegal.com
Jonathan’s notable experience includes
- acting successfully in the seminal notice period case of Newcastle v Haywood [2018] UKSC 22 in the Supreme Court
- Newson-Smith v Al Zawawi [2017] EWHC 1876 (QB), an important committal decision
- Shepherd v Byrne and Partners LLP [2017] EWHC 758 (Ch), a tax professional negligence claim
- Frederick v Positive Solutions Ltd, which settled shortly before the Supreme Court appeal, and
- Santander v RA Legal [2014] EWCA Civ 183, then the leading professional negligence conveyancing case.
