After the fall of France, British Prime Minister Winston Churchill feared that, in German or Italian hands, the ships of the French Navy would pose a grave threat to the Allies. He therefore insisted that French warships either join the Allies or else adopt neutrality in a British, French, or neutral port. Churchill was determined that French warships would not be in a position to support a German invasion of Britain, though he feared that a direct attack on the French Navy might cause the Vichy regime to actively ally itself with the Nazis.