Royal Navy classifications, concealed gun development and treaty flexibility

What are your favorite examples of the Royal Navy shading or evading the truth, and what resulted?

The examples concern useful classifications, concealed development and room for later modifications, although the County armor provisions require distinctions between individual batches and completed refits.

Unicorn's description as a forward aviation maintenance ship is one example of a classification that served a practical purpose. The 15-inch gun's description as a special 13.5-inch weapon made its development appear to continue an existing Royal Navy gun program; a nominal 14-inch gun would have suggested a new program instead. Fleet selects the handling of publicity after HMS Captain's loss as an example of protecting Admiralty control over warship design. Other examples concern conservative speed claims, Spey-engined Phantoms and the County-class cruisers' scope for added armor. There is disagreement about how widely that provision existed across the Counties, alongside a distinction between the ability to fit armor and actually completing the work. U-class submarines provide another example: an advertised training role could coexist with wider operational plans.