Destroyers for bases expands Atlantic security

The United States transferred fifty older destroyers in return for ninety-nine-year leases on Atlantic and Caribbean base sites, while Bermuda and Newfoundland sites were granted separately. American construction strengthened the approaches to North America as well as expanding United States reach. The installations could support British or Canadian forces if invasion forced a withdrawal across the Atlantic, a contingency that still seemed possible in 1940. Britain needed the destroyers because the fall of France and Norway enlarged its escort commitments while combat losses reduced the ships available. Even with Flower-class vessels beginning to arrive, the gap between need and escort strength had widened.