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France and the UK, the largest shareholders in the Suez Canal Company, saw its nationalization as yet another hostile measure aimed at them by the Egyptian government. Nasser was aware that the canal's nationalization would instigate an international crisis and believed the prospect of military intervention by the two countries was 80 per cent likely. He believed, however, that the UK would not be able to intervene militarily for at least two months after the announcement, and dismissed Israeli action as "impossible". In early October, the UN Security Council met on the matter of the canal's nationalization and adopted a resolution recognizing Egypt's right to control the canal as long as it continued to allow passage through it for foreign ships. According to Heikal, after this agreement, "Nasser estimated that the danger of invasion had dropped to 10 per cent". Shortly thereafter, however, the UK, France, and Israel made a secret agreement to take over the Suez Canal, occupy the Suez Canal zone, and topple Nasser.

What nation did Nasser judge impossible to become militarially involved?
Israel