text: Another development regarding the main armament was the adoption of a combined high-angle/low-angle director tower, the HA/LA Mk.IV (TP). This was never entirely satisfactory in the HA mode, and was at least a ton overweight. It was later reworked, somewhat unsuccessfully again, as the Mk.I "K tower" of the Z class. These ships used the Fuze Keeping Clock HA Fire Control Computer. Despite its problems, the L and M class' director tower and its Type 285 radar provided better high-angle fire control than any similar Axis destroyer, the vast majority of which did not have any high-angle fire control system, much less a dedicated AA fire control radar.
  As originally ordered, the class had no close-range armament at all, as the various departments could not agree on what to fit. Arguments raged as to the effectiveness of mounting one or two four-barrelled 2 pdr "pom poms", one pom-pom and one of the  multiple machine guns then in development, one pom-pom and the traditional 0.5-inch (12.7 mm) Vickers machine gun. The argument was stoked by the manufacturing schedules (a second pom-pom per ship would not be available until 1942), the poor performance of the development models of the 0.661 and a number of younger officers (led by Lord Louis Mountbatten) dissatisfied with available anti-aircraft weaponry. Eventually, development of the 0.661 was dropped as it clearly would not be available and effective in a sensible timescale, this simplified the arguments somewhat.