Lord Mark Sedwill, KCMG, FRGS, was formerly National Security Adviser (2017-20) and Cabinet Secretary (2018-20).

He is an Honorary Fellow of St Edmund Hall, having taken the M.Phil. in Economics at the Hall in the 1980s.

After Oxford he pursued a diplomatic career, much concerned with security, and has served as UK Ambassador to Afghanistan and then NATO Civilian Representative in Afghanistan.