Peter Rees QC, the former legal chief of Shell, has joined Thirty Nine Essex Street as a counsel and commercial arbitrator, Legal Week can reveal.

Rees, the one-time head of Norton Rose's global dispute resolution practice, moves to Thirty Nine Essex this week, becoming the chamber's 40th silk.

His departure from Shell in January was a shock to a number of the oil major's advisers, coming just three years after he joined the company from litigation heavyweights Debevoise & Plimpton.