When larger capital ships would force British dock expansion

How soon would larger capital ships force Britain to expand its dockyards without naval treaties?

Probably by about 1924 or 1925, although Britain's large existing yard network meant much of the work could be expansion rather than entirely new construction.

Larger capital ships require docks and support facilities able to receive them throughout their service lives, not merely slips capable of launching them. The likely British expansion falls around 1924 or 1925 if an unrestricted naval race continues. Britain begins with extensive infrastructure, so many projects would be upgrades rather than construction of entirely new yards. The cost still belongs to the capital program and shows how rising ship dimensions pull shore establishments upward with them.