Between 2020 and 2021，the UK was highly active in security and defence activities. First，the UK released the national security strategy delayed by the pandemic，Global Britain in a Competitive Age：the Integrated Review of Security，Defence，Development and Foreign Policy. Second，the UK carried out several operations in Europe，the Indo-Pacific and the Middle East，such as participating in military exercises in the European region within the framework of NATO，actively carrying out the “Indo-Pacific tilt” and strengthening defence security cooperation with Japan and other countries，as well as resolving the Iran nuclear crisis in the Middle East. Third，significant progress has been made in the UK’s arms trade and expansion of security and defence forces. This mainly includes ensuring Britain’s position as a major weapon exporter，establishing a National Cyber Force for cyber-attacks，and a Space Command for space security. Looking ahead，the UK will increasingly rely on defence measures to achieve its national goals in pursuit of its ambitious goal of “Global Britain”.