1956 The Suez Crisis erupted in October 1956 after Britain, France and Israel invaded Egypt to regain control of the Suez Canal. Eisenhower had repeatedly warned London against any such action, and feared a collapse of Western influence in the region. Furthermore, there was risk of a wider war, after the Soviet Union threatened to intervene on the Egyptian side and did invade Hungary to suppress a revolt. Washington responded with heavy financial and diplomatic pressure to force the invaders to withdraw. British post-war debt was so large that economic sanctions could have caused a devaluation of sterling. This would be a disaster and when it became clear that the international sanctions were serious, the invaders withdrew. Anthony Eden soon resigned as prime minister, leaving office with a ruined reputation. The world noted Britain's fall from status in the Middle East and worldwide. Anglo-American cooperation fell to the lowest point since the 1890s. However, the new prime minister Harold Macmillan (1957–1963) restored good terms with Eisenhower and President John F. Kennedy (1961–1963). Intimacy and warmth characterized his relationship with the latter who appointed David K. E. Bruce as ambassador. Lyndon Johnson and Harold Wilson: 1963–1969 After Kennedy's assassination President Lyndon B. Johnson (1963–1969) kept ambassador Bruce but ignored all his recommendations. Bruce sought closer ties with Britain and greater European unity. Bruce's reports regarding Britain's financial condition were pessimistic and alarmist. With regard to Vietnam, Bruce privately questioned US involvement and constantly urged the Johnson administration to allow Britain more of a role in bringing the conflict to an end. The British ambassador was Sir Patrick Dean (1965-1969). Dean was preoccupied with sharp difficulties over Vietnam and British military commitments east of Suez. He promoted mutual understanding but was largely ignored by Johnson because the traditional Anglo-American relationship was decaying and Johnson disliked diplomats. London, furthermore, relied less and less on ambassadors and embassies. Through the US-UK Mutual Defence Agreement signed in 1958, the UK and US resumed military technological cooperation on nuclear weapons, which had been prevented by the 1946 US Atomic Energy Act of 1946 (otherwise known as the Mcmahon Act). Britain's independent nuclear programme was increasingly hampered by funding issues, and the cancellation of the British Blue Streak ballistic missile in 1960 necessitated the purchase of the US Skybolt system. In April 1963, the Polaris Sales Agreement established a basis for the sale of the US UGM-27