Mediterranean ASW and the British submarine force mix

Were Italian forces effective at anti-submarine warfare, and why did Britain use large submarines in the Mediterranean?

Italy had useful ASW advantages in shallow waters, while Britain used T-class boats partly because smaller U-, S-, and V-class submarines were scarce or needed elsewhere.

The shallow Mediterranean was an unusually favourable environment for spotting or attacking submarines, and Italian forces were more effective at ASW than Germany in that setting. The Royal Navy did not use larger T-class boats simply by preference. U-, S-, and later V-class submarines existed in limited numbers and had competing tasks. Theatre geography and the available mix of boats therefore shaped submarine employment together.