It was decided to pursue a derivative of its new Skua dive bomber, of which two prototypes had been ordered for the Fleet Air Arm earlier that year.

The Roc also retained the wing-mounted dive brakes present on the Skua but the mainplane was redesigned with a slight dihedral to obviate the upturned wingtips.

The turret was hydraulically powered by an electrically-driven pump, the guns were fired electrically and had integrated automatic interruption to prevent the tail unit or propeller being hit.

[11] Early flight testing revealed its handling to be not only acceptable but superior to that of the Skua; while not suitable for aerobatic manoeuvres, it demonstrated its steadiness in steep dives.

Production was allowed to continue as the project's cancellation would have caused too much disruption for Boulton Paul; plans were laid to adapt the aircraft to perform target towing and other secondary duties.

These floats, which was largely composed of Alclad, were fitted with pneumatically-actuated water rudders that connected directly with the aircraft's conventional braking system; the tail wheel was also replaced by a mooring ring.

[15] During testing, the first conversion demonstrated direction instability and during December 1939, it crashed at Helensburgh Marine Aircraft Experimental Establishment where it had been transferred at the outbreak of the war.

While the addition of an enlarged ventral fin largely resolved the problem, the effect of the floats on the aircraft's performance was too great to be ignored, as the maximum speed had fallen to only 193 mph (168 kn; 311 km/h), thus plans to form a fighter squadron equipped with Roc floatplanes were abandoned.

The Roc floatplane was rejected in this role as well, resulting in the fleet's requirements for target tugs being fulfilled by landplanes, such as the Miles Martinet, instead.

[19] By August 1940, production of the Roc had ceased and manufacturing resources were diverted to more capable aircraft such as the Fairey Fulmar and the Hawker Sea Hurricane.

[20] During April 1939, preparations commenced for the Roc's entry into squadron service; that same month, the fifth production aircraft was delivered to the Central Flying School to assist with personnel familiarisation.

In the Norwegian theatre, they were used to carry out combat air patrols over the fleet, but were regarded as being of little use, showing inadequate performance when intercepting German aircraft.

Flying underneath the Junkers while the Skuas attacked from above, Day's Roc destroyed one Ju 88 before returning safely to RAF Detling.

[28] On 26 September 1940, during one such patrol, Pilot Officer D. H. Clarke and his gunner, Sergeant Hunt, engaged a Heinkel He 59 seaplane, also on a rescue mission, which had fired on them first.