OK - 49 then...
From the BBC:
Considered to be the most significant turning point in post-war British foreign policy, the Suez Crisis refers to the British decision to join with France and Israel in a military intervention to attempt to prevent General Nasser from nationalising the Suez Canal in the autumn of 1956. Nasser was promoting Arab nationalism throughout the Middle East and had become an increasing source of irritation to the British and the French.
The Anglo-French assault upon Egypt, which began on 31 October 1956, provoked a furious response from the USA. President Eisenhower's condemnation of the attack triggered a sterling crisis which forced the government to withdraw from the venture. This angered the French, and further revealed Britain's growing dependence on the support of the US.
One of the first signs of a weakening UK. And yet barely 12 months later that utter ar$e Duncan Sandys started the destruction of the RAF which has continued ever since.