Excerpts from Books and Wikipedia
"The British commander Field Marshall Lord Gort decided his principal duty was to preserve his army and planned for its evacuation from the beaches of northern France and Belgium. . . . Incessantly attacked by a German planes, with little cover for the withdrawing units or for the ships, Operation Dynamo succeeded between May 28 and June 4 in bringing to England more than 338,000 soldiers, including 120 thousand French personnel." [Furtado: 1001 Days]