Stephen became National Security Adviser in March 2021.
Prior to this he was Permanent Secretary at the Ministry of Defence from 2016-2021 and Permanent Secretary for Department of Energy & Climate Change from 2013-2016.
Stephen spent nine years at the Shareholder Executive, now UK Government Investments, where he was appointed Chief Executive in June 2007. He previously worked in investment banking and strategic consultancy.
Stephen also sat on the board of the London Organising Committee of the Olympic Games and Paralympic Games and was a trustee of the Charities Aid Foundation.