The end of the Palestine mandate and the chaos surrounding it had significant implications for both neighbouring Transjordan and British imperial interests in the Middle East. This chapter explores how the two allies sought to deal with this issue. Based on significant new sources, it corroborates Avi Shlaim's disputed claim that Britain gave King Abdullah the 'green light' to use the Arab Legion to occupy the areas of Palestine allotted to the Arab state by the UN, thus creating an enlarged Jordanian state alongside a new Jewish state, Israel. Paying particular attention to the role of Glubb and the Arab Legion during the first, civil war phase of the 1948 Arab-Israeli War, this chapter reveals that, after a meeting between the British Foreign Secretary, the Jordanian Prime Minister, and Glubb in February 1948, the Arab Legion commander actively sought to thwart the efforts of the Arab irregular forces and find a military accord with the Zionists. Glubb was not the architect of the Greater Transjordan scheme, as some have argued, but he was responsible for its implementation. In 1948 Glubb and the Arab Legion emerged as crucial tools for securing British and Jordanian interests in post-mandate Palestine.