The Transjordan Frontier Force was formed, on 1 April 1926, as a para-military border guard to defend Trans-Jordan's northern and southern borders. The TJFF was also an Imperial Service regiment whose Imperial Service soldiers agreed to serve wherever required and not just within the borders of their own colony, protectorate or, in the case of the Transjordan, mandate. This was in contrast to the Arab Legion, which was seen more as an internal security militia, deriving from the troops of the Arab Revolt and closely associated with the Hashemite cause. The Amir Abdullah was an Honorary Colonel of the Trans-Jordan Frontier Force from its inception.
The Transjordan Frontier Force (TJFF) was established at Sarafand on 1 April 1926 with a cadre drawn from the Arab Legion and quickly grew to three cavalry squadrons, each of 120 men each, and an infantry unit. Its first commander was Lieutenant-Colonel FW Bewsher, DSO, OBE, MC,Other units, such as a camel squadron and mechanised units, were added subsequently.
The TJFF would be equipped in a conventional manner, with modern weapons, whilst the Arab Legion would, initially, remain a traditional force, looser in structure and without training in alien technology. Accordingly, the Arab Legion transferred its inventory of machine guns, artillery, and radios.
The TJFF replaced the disbanded British Gendarmerie which previously had the task of protecting Transjordan's borders.
In the post-war era, with the independence of the Transjordan and of Palestine looming, there was no longer a requirement for an Imperial Service unit in the region. On 9 February 1948 the 3,000 man Trans-Jordan Frontier Force was disbanded and most of its members transferred to the Arab Legion.
The TJFF served under Headquarters, British Forces in Palestine and Trans-Jordan, from 3 Sep 1939 till 9 Feb 1948. The O.C. TJFF was a British lieutenant colonel, with Headquarters at Zerqa. Second-in-command was a British major, responsible for administration, workshops, quartermaster's stores and pay. The adjutant, another British major, was responsible for training and personnel and was aided by an assistant adjutant who was an Arab officer.
The squadrons and companies were all commanded by British majors, with another British officer as second-in-command. The cavalry squadrons were organised into three rifle troops (36 men) and one machine gun troop (36 rifles and 4 MGs). The normal tactical and reconnaissance unit however, was the half-squadron or half-company and these were commanded by local captains. Each half-squadron or company consisted of two troops, led by local lieutenants and captains.
By the end of 1927 there were 39 officers, including 17 British, 12 British warrant officers, three staff sergeants and 676 other ranks. In 1930 there were 17 British officers, two in each of the four squadrons and companies with the remainder at Force HQ. In 1935 there were 24 British officers - the OC, seven majors and sixteen captains.
The TJFF spent its first six months training in Palestine at Sarafand then at Shunet Nimrinfrom (from October 1926) in the Jordan Valley. TJFF HQ moved to Zerqa east of the Jordan River in Trans-Jordan. The cavalry squadrons were based at Zerqa and the camel company was based at Ma'an. In 1929, the TJFF was called upon to help deal with Arab unrest in Palestine. The camel company moved to Jericho and a cavalry squadron went to Jisr el Majamie. A second cavalry squadron was raised and dispatched as reinforcement in early 1930.
In 1930, the mechanised company, based at Ma'an, was formed and later that year the camel companies were disbanded. Motorisation extended the range of the TJFF further out into the desert. In 1930 the TJFF had 980 men, including 28 Jews.
source - Wikipedia