The Sudan became a condominium ruled jointly and equally by the United Kingdom and Egypt following the British victory over the Mahdists at the Battle of Omdurman on 2 September 1898. After the Great War (First World War) and the break up of the Ottoman Empire, there was increased tension in Egypt and the Sudan. The assassination of the Governor-General of the Sudan in 1924 led to the British government imposing demands on the Egyptian government which resulted in the dissolution of the condominium.

In 1925, the country was made a Protectorate of the United Kingdom. A local armed police or militia was formed that year entitled the Sudan Defence Force (S.D.F.) to maintain law and order in the country following the withdrawal of Egyptian officers and units from the Sudan.

In 1930, British Troops in the Sudan was a subsidiary command of British Troops in Egypt for the purposes of administration, although it remained separate operationally. The commandant of the Sudan Defence Force was a Temporary Brigadier, who held the rank of Local Major General. He also held the dual responsibility as General Officer Commanding British Troops in the Sudan. He had a small staff of one Colonel and fourteen other officers to assist him.

There were usually two British infantry battalions posted to the Sudan between the wars. By the outbreak of the Second World War, this had been increased to three. The entry of Italy into the war potentially made the Sudan vulnerable to attack from Eritrea and Abyssinia. The Commander-in-Chief, Middle East (General WAVELL) decided to attack the Eritrea and Abyssinia, which also removed the potential threat to the sea routes to the Far East.

The build up of forces commenced in September 1940 with the arrival of the 5 Indian Infantry Division from India. It only consisted of two brigades, so the three British battalions were absorbed into the division. Local probing attacks commenced in November, with the 4 Indian Infantry Division arriving from Egypt in December 1940. This allowed the advance into Eritrea to commence in January 1941.

Both Indian formations advanced rapidly until they met fierce resistance at the Keren pass. The fighting there lasted from 2 February until 27 March 1941. Eventually, through a determined series of attacks and sound tactics, the Indian formations forced the Italians to withdraw, and Eritrea was secured. The 4 Indian Infantry Division was sent back to Egypt in mid April 1941, but the 5 Indian Infantry Division remained to drive southwards to meet up with the South Africans in May. A coordinated attack on the Toselli Pass by the Indians and South Africans forced the main elements of the Italian Army to surrender on 19 May 1941.

The Sudan then returned to a quiet backwater, with a military presence to police the country and garrison Eritrea. The last British troops left the Sudan on 16 August 1955.