By late May, following the evacuation of British forces from Dunkirk, France, in Operation Dynamo, the Royal Navy was in immediate need of ships, especially as they were now fighting the Battle of the Atlantic in which German U-boats threatened Britain's supplies of food and other resources essential to the war effort.
I slutningen af maj efter evakueringen fra Dunkerque i Operation Dynamo havde Royal Navy et akut behov for skibe, især da de nu stod overfor Slaget om Atlanten hvor tyske ubåde truede Storbritanniens forsyninger af mad og andre vigtige ressourcer til krigsindsatsen.