Britain’s 2018 “fusion doctrine” was an effort to bring together the elements of national power to enhance the country’s security and strategic interests under the post-Brexit “global Britain”. 

Its architect, Lord Mark Sedwill, is today’s guest. He assesses the key global trends, challenges and crises—Donald Trump’s second administration; Chinese assertiveness; Russia’s war on Ukraine and the unfolding tragedy in Gaza—and talks about what a fusion doctrine might look like for 2025, including the dynamic elements of rapid technology advances and turmoil in international trade.

Mark held the dual roles of national security adviser and cabinet secretary—or the head of the UK civil service—under Prime Ministers Theresa May and Boris Johnson. He’s previously served as UK ambassador to Afghanistan, the NATO senior civilian representative in Afghanistan and the head of the Home Office. He’s now a Member of the UK House of Lords and chair of the think tank International Institute for Strategic Studies.