Sidley Austin's London managing partner Tom Thesing, a Sidley lifer, began his career at the firm's Chicago headquarters over 30 years ago. Following a move to London in the 1990s, Thesing was promoted to partner in 2001. In 2005, he was promoted to London corporate head and in 2018 took over the reins as managing partner. Under his watch, the London office has continued a decade-long year-on-year revenue increase, breaking through the £100 million mark in 2021.