Stuart joined Citigroup in July 2011 as Vice Chairman EMEA Banking. Until December 2010, he was the Senior Partner, worldwide, of Clifford Chance LLP, one of the world's leading law firms where he chaired the firm's Partnership Council, the supervisory board of the worldwide firm.

He joined Clifford Chance in 1976 and was elected to the Partnership in 1984. He held various roles within the firm including leading the Banking and Finance practice areas between 1999 and 2003, becoming the Senior Partner in 2003.

Stuart chairs TheCityUK which promotes financial services. Stuart is also a member of the business Advisory Forum of the Saïd Business School, Oxford University. He is a non-executive director of Legal and General Insurance and is a Patron of the Whitehall Industry Group. Stuart is a member of the CBI and was for a number of years Chair of the London Region and sat on the Chairman's and other committees. He is an International Envoy for London.