The Royal Navy ended the First World War building light cruisers and scout cruisers, while the Hawkins class's 7.5-inch guns helped shape the later eight-inch treaty boundary. Earlier armoured cruisers had carried 9.2-inch guns, and postwar work raised the question of a new heavy cruiser. With 16- and 18-inch capital ships under consideration, a 12-inch cruiser gun would have left a clear difference in armament and used a calibre Britain knew well. The suggestion that such a weapon was being considered rests on limited reading of the design studies, so it remains a qualified reconstruction. In the counterfactual, delaying the Washington negotiations until 1924 or 1925 could have allowed larger British capital ships and 12-inch cruisers to influence the negotiated limits.
Notable Point · 2:43:13-2:46:12
A possible Royal Navy 12-inch heavy cruiser
Without the Washington treaty timing, British cruiser categories and gun calibers might have developed around much larger ships.