The Lion class was a class of six fast battleships designed for the Royal Navy (RN) in the late 1930s. They were a larger, improved version of the preceding King George V class, with guns. Only two ships were laid down before the Second World War began in September 1939 and a third was ordered during the war, but their construction was suspended shortly afterwards. The design was modified in light of war experience in 1942, but the two ships already begun were scrapped later in the year. None of the other ships planned were laid down, although there was a proposal in 1941 to modify one of the suspended ships into a hybrid battleship-aircraft carrier with two 16-inch gun turrets and a flight deck. Preliminary work for a new design began in 1944 and continued for the next year or so until the RN realised that they were unaffordable in the post-war financial environment. Design and description The design of the Lion-class battleships was influenced by the terms of several arms control treaties of the 1920s and 1930s. The Washington Naval Treaty of 1922 had banned new battleship construction, with certain specified exceptions, for a decade. The London Naval Treaty of 1930 extended the ban for five more years, which meant that almost all the First World War-era ships would be eligible for replacement by the Washington Treaty's rules when the London Treaty expired. The British government intended for the 1935 Second London Naval Disarmament Conference to prevent a naval arms race that Britain could ill afford, but the Japanese refusal to sign the resulting Second London Naval Treaty of 1936 thwarted that hope. The three signatories, Britain, France and the United States had agreed to limit the size and gun calibre for the battleships that would be built by the signatories. They were restricted to standard displacement and a main armament calibre of . This dictated the choice of the 14-inch gun for the main battery of the King George Vs (KGV). The treaty contained an "Escalator Clause" that would increase the maximum allowable calibre to 16 inches if the Japanese government failed to sign; this was triggered in April 1937. The Board of Admiralty then began preliminary design work on a 35,000-long-ton ship armed with 16-inch guns and it was promising enough that the Director of Naval Construction (DNC) was ordered to further investigate such designs. To