Britain's submarine-ban campaign concealed a strategic tradeoff

Why did Britain not make an international submarine ban a walk-away treaty issue?

Because the Royal Navy still needed submarines for its own plans, while the abolition campaign also helped preserve treaty freedom to build many light anti-submarine escorts.

Britain maintained one of the world's largest submarine fleets and expected submarines to serve as mobile minefields in Far Eastern defence plans. A real ban would therefore undermine concepts such as ambushing a Japanese advance toward Singapore. By pressing abolition publicly, however, Britain could argue for freedom to build large numbers of sub-2,000-ton anti-submarine sloops and escorts outside treaty limits.