The London framework imposed no meaningful aggregate limit on compliant sloops. At about £70,000 per Bittern-class ship, twenty vessels a year would cost roughly £1.4 million. Compared with emergency wartime construction and the losses caused by inadequate escort, that was a modest interwar investment. Their scarcity came from governments choosing not to fund escort capacity that later became vital.
Notable Point · 2:42:18-2:46:06
The missing sloops were a political choice, not a treaty limit
At roughly £70,000 each, interwar sloops were affordable enough that their scarcity reflects procurement policy rather than treaty prohibition.