Due to supply problems and the persistent failure by the Royal Navy to develop a suitable dual-purpose weapon for destroyers, they were fitted with whatever armament was available. Advances in radar and weaponry were incorporated as they came available.
Supply problems and the Royal Navy’s failure to produce an adequate dual-purpose weapon meant that destroyers were outfitted with any weapons that were obtainable. As new radar and weaponry became available, these systems were incorporated into the ships' arsenals.