The County-class and the Seaslug missile were interim solutions and the new Sea Dart anti-aircraft missile would have speed and accuracy to ensure a hit without requiring a nuclear warhead. First Lord Mountbatten doubted the usefulness of tactical nuclear weapons by 1962, due to escalation theories, scientific advice and greater evidence of fallout consequences, leading to the Partial Nuclear Test Ban Treaty in 1963. There were also staff and space difficulties with carrying nuclear warheads on confined destroyers. As early as 1952, Air Chief Marshal John Slessor (Chief of the Air Staff) the most influential defence Advisor to Winston Churchill considered the Navy irrelevant in a nuclear war, he first defined, the role of RN was "uncertain" as a pretext to maintain a large fleet and required only for political reasons. The collapse of the 1956 Suez operation and the huge impact of the British hydrogen bomb tests in 1954-57 led to the 1957 review of Britain's defences, reliance on nuclear deterrence by strategic aircraft, missiles and missile submarines and doubt that a nuclear war would last long enough to require trans-Atlantic convoys. And corresponding doubt whether major conventional war was still possible on the basis of the last 1954-5 HC speeches of Churchill and Eisenhower, justified large cutbacks of British and American large ship, destroyer and carrier programme and the future role and relevance of the Royal Navy was "unclear" moving the RN to more limited, East of Suez task forces, with gun and Seaslug- and Seacat-armed destroyers escorting medium British aircraft carriers with only a limited nuclear strike capacity against ships and cities equipped with Blackburn Buccaneer S.1 (and then the improved S.2) strike aircraft mainly aimed to deter regional powers such as Indonesia Early versions of the equivalent US missile system RIM-2 Terrier, like Seaslug, relied on beam riding and needed a nuclear warhead variant to compensate for inaccuracy at low level and range. However, by 1962, the US was concentrating on the medium range radar guided RIM-24 Tartar and long range RIM-8 Talos, which had success against long range North Vietnamese aircraft from 1968. The Royal Air Force's semi-active land-based Bristol Bloodhound was unrelated to Seaslug development, but drew top scientists away from RN work.