This is the "agreement" that is referred to in the quote in my last post:

"Shlaim, in his well-argued, generally well-founded book had maintained that (a) years of Zionist-Hashemite contacts and shared political interests had resulted, in 1946-47, in the conclusion of an unwritten agreement between the leadership of the Yishuv and 'Abdallah, king of Jordan, not to fight each other but to split Palestine between them, with the Hashemites (rather than the Palestinians) receiving what is today called the West Bank, and eventually to make peace; (b) in early 1948, Britain tacitly approved the Yishuv-Hashemite agreement by supporting a Jordanian takeover of the West Bank (rather than the creation in that territory of an independent, Husayni-led Palestinian state, as the UN General Assembly had ruled), and cautioned 'Abdallah not to attack the Jewish state; (c) the Yishuv-Hashemite agreement, while somewhat shaken, in effect weathered the Jewish-Palestinian battles of November 1947-May 1948, and resulted in limited and indecisive warfare between the Israel Defence Forces and Jordan's army, the Arab Legion, in May 1948-April 1949; and (d) following the war, 'Abdallah wanted to reach peace with Israel but due to the internal weaknesses of his position and Israeli unwillingness to make concessions, no peace treaty was achieved."