London Naval Treaty

The Treaty for the Limitation and Reduction of Naval Armament, colloquially known as the London Naval Treaty, was an agreement between the United Kingdom, the Empire of Japan, France, Italy and the United States, signed on 22 April 1930, which regulated submarine warfare and limited naval shipbuilding. Ratifications were exchanged in London on October 27, 1930, and the treaty went into effect on the same day. It was registered in League of Nations Treaty Series on February 6, 1931.

Conference
The signing of the treaty remains inextricably intertwined with the on-going negotiations which began before the official start of the London Naval Conference, evolved throughout the progress of the official conference schedule, and continued for years thereafter.

Terms of the Treaty
The terms of the treaty were seen as an extension of the conditions agreed in the Washington Naval Treaty. That treaty had been an effort to prevent a naval arms race after World War I.

The Conference was a revival of the efforts which had gone into the Geneva Naval Conference of 1927. At Geneva, the various negotiators had been unable to reach agreement because of bad feeling between the British Government and that of the United States. This problem may have initially arisen from discussions held between President Herbert Hoover and Prime Minister Ramsay MacDonald at Rapidan Camp in 1929; but a range of factors affected tensions which were exacerbated between the other nations represented at the conference.

Under the Treaty, the standard displacements and gun calibres of submarines were restricted for the first time, thereby putting an end to the 'big-gun' submarine concept pioneered by the British M class and the French Surcouf. The Treaty also established a distinction between cruisers armed with guns no greater than 6.1 inches (155mm) calibre ("light cruisers" in unofficial parlance), from those with guns up to 8 inches (203 mm) calibre ("heavy cruisers"). The number of heavy cruisers was limited - the US was permitted 18 with a total tonnage of 180,000, the British 15 totalling 147,000 and the Japanese 12 totalling 108,000 tons. For the light cruisers no numbers were specified but tonnage limits were 143,500 tons for the US, 192,200 tons for the British and 100,450 tons for the Japanese.

Article 22 relating to submarine warfare declared that international law applied to them as to surface vessels. Also merchant vessels which did demonstrate "persistent refusal to stop" or "active resistance" could 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; and in that year, Italy retired two battleships, twelve cruisers, 25 destroyers, and 12 submarines—in all, 130,000 tons of naval vessels. Active negotiations amongst the other treaty signatories continued during the following years. This was followed by the Second London Naval Treaty of 1936.