The Otranto Barrage was a naval blockade of the Otranto Straits between Brindisi and Corfu, intended to prevent the Austro-Hungarian navy gaining access to the Mediterranean Sea. Although it did keep Austro-Hungarian surface ships in the Adriatic, it had little effect on submarines, which routinely passed through the Barrage to conduct anti-shipping operations in the Mediterranean. The idea of the Barrage was first brought up by First Lord of the Admiralty Winston Churchill at the May 1915 conference in Paris, on the eve of Italy’s entry into the war. Churchill offered to supply 50 fishing trawlers and 50 miles of submarine indicator nets, in return for the Italians providing crews and armament. The Italians declined, realising that manning and arming the craft would be a significant challenge. During the Dardanelles campaign, British trawlers proved very useful, and as the submarine war in the Mediterranean intensified, the Italians realised that they did not have enough small vessels for anti-submarine duties.