Hat tip to Maurice Ostroff: In 1922-23, contradicting the terms of its mandate, the British excised 80% of the area intended for the Jewish National Home in a grievous act of perfidy and gave it to the Arabs instead.
In the almost-empty area east of the Jordan River, it created a new state named Transjordan, which has since been renamed the Hashemite Kingdom of Jordan.
These facts are confirmed on the Jordanian web site http://www.kinghussein.gov.jo/his_transjordan.html in the following words.
"On May 15, 1923, Britain formally recognized the Emirate of Transjordan as a state under the leadership of Emir Abdullah. This angered the Zionists, as it effectively severed Transjordan from Palestine and so reduced the area of any future Jewish national home in the region".