How far Britain took 20-inch gun ideas

Did Britain prototype 20-inch naval guns or plan a ship comparable to other extreme postwar designs?

There are signs of conceptual work, but no proof of gun trials or a committed comparable ship.

Some British designers appear to have explored the idea of a 20-inch gun after the First World War. No evidence indicates that a prototype reached proof firing. There is likewise no proof that Britain intended to build a ship comparable to the enormous designs implied by the question. Conceptual work should not be mistaken for a funded weapon or construction program.