On July 3 1940, soon after the collapse of the French front and France's request for an armistice, a reluctant Royal Navy commander opened fire on the French Navy squadron at Mers-el-Kebir. Some 1,300 French sailors lost their lives. The driving force behind this extraordinary event was the British government's determination that the French Fleet would never fall into the hands of the Axis powers. A combination of mistrust, dissembling, poor communications, and outright enmity over the preceding month had catastrophic results, both for the individuals concerned and for the future of Franco-British naval relations. The late David Brown's detailed account finally conveys an important objective understanding of the course of events that led up to this tragedy. The work makes extensive use of primary sources such as correspondence, reports and signals traffic from the British Cabinet to the admirals, the commanders-in-chief, and the liaison officers.