Ken McCallum – Director General MI5

Ken McCallum is the Director General of the Security Service (known as MI5). He is an MI5 officer with experience across the full spectrum of the organisation’s national security and intelligence work.

National Cyber Force

The National Cyber Force (NCF) is a partnership between defence and intelligence. It is responsible for operating in and through cyberspace to counter threats, disrupting and contesting those who would do harm to the UK and its allies, to keep the country safe and to protect and promote the UK’s interests at home and abroad. In addition to GCHQ and the Ministry of Defence, the Secret Intelligence Service and the Defence Science and Technology Laboratory are core partners bringing cutting-edge espionage and research techniques.


Ken was appointed Deputy Director General of MI5 in April 2017, with responsibility for all of MI5’s operational and investigative work. In 2018 this role saw him take charge of the MI5 response to the attempted assassination of Sergei Skripal. Between 2015 and 2017 Ken held the role of Director General Strategy, focussing on shaping new legislation and further strengthening MI5’s partnerships with SIS and GCHQ.

In 2012, Ken took charge of all counter-terrorism investigations and risk management in the run-up to, and during, the London Olympics. After the Games, he undertook a secondment to the Department for Business, Innovation and Skills (now BEIS) leading on digital issues, and building his experience beyond the national security domain. Following his return to MI5 he retained links to the wider public sector, serving for three years as a Non-Executive Director on the board of the Nuclear Decommissioning Authority.

The first ten years of Ken’s career were focused on Northern Ireland-related terrorism. Senior operational roles in countering Islamist extremist terrorism followed, and a period leading on cyber security, where he expanded MI5 engagement with the private sector.

Personal life

Ken grew up in Glasgow and holds a degree in Mathematics from Glasgow University. His out-of-work life is dominated by trying to be an active father. When work/parenting allows, he enjoys hiking in the mountains.

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