Would Britain still have built HMS Dreadnought?

Would Britain still have introduced HMS Dreadnought without a direct German naval challenge?

Probably yes, because Britain was responding to a wider international battleship race and wanted a design that reset the competitive count in its favor.

Italy, France, Russia, Japan, the United States, and South American powers all formed part of the broader naval competition. Germany mattered, but the all-big-gun battleship was not solely an anti-German project. A German decision not to copy it might instead have reduced later Anglo-German tension.