Fisher's 20-inch Incomparables replace the large light cruisers

What if Courageous, Glorious, and Furious had been built as six-gun, 20-inch Incomparables?

They would provoke an escalating capital-ship race, reshape the Admiral class, and probably postpone meaningful naval arms limitation.

Building Courageous, Glorious, and Furious as six-gun, 20-inch Incomparables would provoke larger American and Japanese capital-ship responses. Subsequent British battleships would also need to answer the new armament, with the Admiral class recast as fast battleships carrying perhaps eight or nine 20-inch guns. The expected result is a more expensive arms race and naval treaties delayed into the 1930s, if agreement remains possible. Ammunition alone creates a large design burden: a rough calculation using 200 rounds per gun and rounded two-ton shells produces about 2,400 tons of projectiles. A firing interval of around 40 seconds would already be ambitious before allowing for aiming. The scenario therefore changes both international competition and the practical weight and firing limits of the ships.