The answer treats naval strength as the indispensable defense of an empire connected by sea. The major personnel and spending cuts of the mid-1920s were possible because the Washington settlement reduced the external construction threat. If American and Japanese programs continued, Britain could not safely assume treaty-based security while shrinking its own fleet. It would instead preserve manpower and construction sufficient to secure trade and imperial routes, even at substantial domestic cost.
Notable Point · 3:17:49-3:19:09
Why Britain would fund naval expansion without treaty security
The Geddes-era cuts depended on treaty-backed fleet reductions; without them, Britain would have to buy maritime security through construction.