How treaty-exempt sloops answered a submarine-only threat

A German fleet concentrated on U-boats would have let Britain direct more construction toward submarine escorts. The Royal Navy already had interwar sloop programmes and could have accelerated Flower-class corvettes and Hunt-class escort destroyers, perhaps ordering them earlier. Among the London Naval Treaty's Article 8 conditions for exempt vessels were displacement below 2,000 tons, a designed speed no greater than twenty knots and no torpedoes. Qualifying escorts could therefore be built without the treaty's main numerical restrictions. Even adding an air threat would have left Britain freer to concentrate battleships and fleet carriers against Italy or in the Far East. German surface raiders forced Britain to retain forces capable of fighting enemy warships as well.