James was Managing Partner of Mishcon de Reya 2020 to 2026. He is a litigator who has been involved in a number of the highest profile cases of the last 20 years, including acting for Deborah Lipstadt in her defence of the claim brought against her by the holocaust denier, David Irving (which case was made into a film, Denial); for Gina Miller in both her recent Supreme Court challenges relating to Article 50 and, in 2019, prorogation; for the Jewish Labour Movement in its referral of the Labour Party to the EHRC; and for several other politicians of all hues over the last 15 years or so.
He received an Honorary Doctorate from the University of Law in 2018 and in 2020 was named Lawyer of the Year by Legal Business for his central role in the growth of the Firm over the past 20 years, work in the Supreme Court ruling on R (on behalf of Miller) v The Prime Minister and in acting for Jewish Labour Movement on antisemitism in the Labour Party. In 2024, James was appointed as a Visiting Fellow at the University of Oxford.
James has sat as a trustee and chaired several charities, particularly in the refugee space.