It was assumed the targets would "jink" at 1G, so the missile needed to maneuver at 4G at sea level and 2.5G at 40,000 ft. Additional requirements were the ability to switch between targets in 6 seconds.The designers ultimately selected a maximum range of 30,000 yards, which included 6,000 yd (5.5 km) of coasting after motor burn-out.

The Task Force Ship would be capable of 30 kn (56 km/h) and would tasked with fleet air defence. Work on what became Sea Slug began in 1949 under 'Stage 1' of the Royal Navy's post-war missile program. Seaslug was intended to engage high-flying targets such as reconnaissance aircraft or bombers before they could launch stand-off weapons. This was about 50% better than the contemporary US When the deployment of the Seaslug was first being considered, three classes of custom missile-firing ships were considered. The Armstrong Whitworth Sea Slug was the Royal Navy's first beam riding surface to air missile and was fitted to County Class destroyers, which were actually cruisers, but falsely identified by the Navy as politicians believed Cruisers were obsolescent. In contrast, the American Terrier missile was somewhat shorter at 13 ft 6 in (4.11 m), but this required an additional tandem booster which took the overall length to 28 ft 6 in (8.69 m).In 1954, during another review of the Navy's future operations, consideration turned from a "hot war" against the Soviets to a series of "warm wars" in the The designs were continually modified in order to find a suitable arrangement. Development made use of on an earlier programme by the Fairey Aviation Company known as "LOPGAP" (The missile had four wrap-around booster motors which separated after launch. When they separated because the extreme drag made by the rings all around the missile, the solid fuel sustainer The County-class destroyers were specifically built to carry Seaslug and its associated control equipment. After separation, the main motor ignited to power the missile to the target. It was, however, limited by the complicated handling arrangements and since each County class ship carried only a single fire-control radar only one target could be engaged at once, though two missiles could be fired against it.

This is one of the final tests at the Woomera testing range in Australia, and used a radio controlled Meteor jet as a target.

The DPRC also began to have concerns about guiding Red Heathen at its 100,000 yd (91 km) maximum range. The weapon was intended to counter high-altitude nuclear-armed bombers before they could release their weapons.

After the Second World War, Armstrong Whitworth concentrated its guided missile work at the plant, including the development of the Sea Slug surface-to-air missile. In 1968 Hawker Siddeley Dynamics, who had by then absorbed the Armstrong Whitworth company, closed the site with the loss of 2,260 jobs.

Armstrong Whitworth "Sea Slug" - боевой слизень на службе Короны - Альтернативная История Work on what became Sea Slug began in 1949 under 'Stage 1' of the Royal Navy's post-war missile program. The weapon was intended to counter high-altitude nuclear-armed bombers before they could release their weapons.

To this end, they accepted the use of liquid fuels in spite of the Navy's concerns with these fuels on ships.

Some of the County-class destroyers were sold to Chile for the Existing Stooge airframes continued to be test-fired for a time.For unclear reasons, considering the Air Ministry was also working on several missile designs of their own.RN and RAF standards of the era counted "hits" under the NATO ADM 1/28039 standard "K15", meaning the target would be destroyed within 15 seconds of a hit. Seaslug was a first-generation surface-to-air missile designed by Armstrong Whitworth (later part of the Hawker Siddeley group) for use by the Royal Navy.

Some of the County Class destroyers were sold to Chile for the