Covert action has long been a central instrument in British foreign policy. In an era of global decline, it has been used by successive Prime Ministers and Foreign Secretaries to fill the gap between British obligations and strength. Despite this, British covert action remains a deeply misunderstood topic. Most Unusual Measures examines British approaches to covert action since 1945. It explores how and why secret government strategy has evolved from the aftermath of the Second World War, through the Cold War and decolonisation, and into the twenty-first century. Focusing on the changing targets, competing interests, departmental rivalries, and the personalities of those involved, Most Unusual Measures assesses the British ‘way’ in covert action.