The London Naval Treaty was an agreement between the United Kingdom, Japan, France, Italy and the United States, signed on April 22, 1930, which aimed to regulate submarine warfare and limited military shipbuilding.

It was an extension of the conditions agreed in the Washington Naval Treaty and is officially termed the Treaty for the Limitation and Reduction of Naval Armament. It was a revival of the Geneva Naval Conference of 1927 which had been unable to reach agreement because of bad feeling between the British Government and that of the United States.

The signatories agreed to build no new capital ships until 1937. A number of existing capital ships were scrapped. No existing vessels were to be converted to aircraft carriers. The construction of submarines was limited to vessels under 2,032 metric tons. The total completed tonnage of cruisers (split into heavy cruisers with guns exceeding 6.1 inches (155mm) calibre and light cruisers with smaller guns), destroyers and submarines to be built by 1937 was limited as was the individual tonnage in each category.

The articles relating to submarine warfare declared that international law applied to them as to surface vessels. Also merchant vessels which did not demonstrate "persistent refusal to stop" or "active resistance" could not be sunk without the ship's crew and passengers being first delivered to a "place of safety".

The next phase of attempted naval arms control was the Second Geneva Naval Conference in 1932.

See also: Second London Naval Treaty

Links

• Text of the treaty