The outbreak of war focused minds. Apart from the AA armament issue concerns started to be raised about progress generally. By February 1940 the two factors led to a proposal to change the design of four of the 'L's and fit a main armament of 4-inch (102 mm) Mark XVI* guns in Mark XIX High Angle/Low Angle (HA/LA) twin mounts as used as secondary armament in the "Southampton"-class cruisers already in service and main armament in the "Black Swan" class of sloops then under construction. Associated changes were provision of two quadruple 0.5-inch (12.7 mm) machine guns. All ships of this class except "Lightning" and "Laforey" carried a four-barrel 2 pdr pom-pom.