In assessing Britain's part in the origins and consequences of the June 1967 War, it is useful to bear in mind a contemporary comment by a shrewd Israeli observer: “Britain's strength is not negligible, but it is greater in causing harm than in being beneficial.” Arabs as well as Israelis would have agreed. To the British, the lack of power came as a revelation, though in an unexpected way. In the initial phase of the crisis, the Cabinet assumed an adequacy of military resources and debated the possibility of another Suez expedition – this time without the mistakes of 1956. The motives for possible intervention were to prevent an Israeli preemptive attack that would have profound consequences for the Middle East, above all for Israel. A possible war might even destroy the United Nations by bringing the international organization into a conflict of cataclysmic proportions beyond its capacity to resolve. Faced with what they believed to be an agonizing choice, to intervene or not to intervene, the British were overtaken by events. During the war they were universally blamed by the Arabs for colluding with the Israelis, whereas in fact they had not. The dual theme of saving the Israelis from themselves and preserving the United Nations runs through British thought at the time, but only in the last stage or aftermath did the British significantly influence the course of events.

Six months after the Six-Day War, the British proposed and sustained UN Resolution 242, which was, to the British at least, the epitome of an evenhanded formula. Just as the Balfour Declaration had been incorporated by the League of Nations as part of the mandate, so also did Resolution 242 become a landmark in the history of the United Nations. It corrected the Jewish tilt of the Balfour Declaration, which had included as almost an afterthought the guarantee that the Jewish national home must not damage Arab interests. From the British perspective, the Balfour Declaration loomed large from the beginning to the end of the year, which marked the declaration's fiftieth anniversary. One of the ironies of the crisis is that the events of the war transformed the military and political domination of Palestine at the same time that the British pondered how best to celebrate the anniversary or rather to let it pass by while saying as little as possible.