What Britain could build after abandoning treaty limits

Could Britain abandon the naval treaties and rush-build a 50,000-ton fast battleship with 18-inch guns in 1939-40 while also building Vanguard-type ships?

Not with 18-inch guns or both programs at once; a large fast 16-inch battleship was more plausible, but yard and weapon-development limits still applied.

The Royal Navy was already building as quickly as wartime yards and programs allowed, so simply opening the Treasury could not erase industrial lead times. An 18-inch gun was not active enough to support the proposed 1939-40 ship, whereas 14-, 15-, and 16-inch work offered realistic starting points. On about 50,000 tons standard, the panel sketches a fast design with three or perhaps four triple 16-inch turrets. Building several such ships would consume the same slips and resources that otherwise supported alternative battleships, while carrier construction still had to continue.