Sudan Defence Force

The Sudan Defence Force (SDF) was a British Army unit formed in 1925, as its name indicates, to maintain the borders of the Sudan under the British administration. During the Second World War, it also served beyond the Sudan in the East African Campaign and in the Western Desert Campaign.

Between 1898 and 1925 Sudanese soldiers served in separate infantry battalions of the Egyptian Army, under British and Egyptian officers. These were designated as either "Sudanese Battalions" or "Arab Battalions" according to their region of recruitment within the Sudan. By contrast to the bulk of the Egyptian Army, who were recruited through annual conscription, the Sudanese units enlisted only long-serving volunteers.

Following a mutiny of Sudanese troops in 1924, and at a time of unrest in Egypt itself, the garrisoning of the Sudan was put on a new basis. Egyptian military units and Egyptian officers of Sudanese battalions were transferred back to Egypt itself. The Sudanese troops remaining were incorporated into the newly created Sudan Defence Force. The junior commissioned officer and NCO positions previously held by Egyptian personnel, were now open to "Sudanisation". A military academy was opened in Omdurman to train the new Sudanese officer corps, most of whom were Muslims from the north. By 1939 the SDF numbered 5,000 officers and men.

The Sudan Defence Force consisted of a number of battalions, misleadingly styled 'Corps', each of which had a set area of operations:

In peacetime, the SDF comprised approximately 4,500 regular Sudanese soldiers. During the Second World War, the SDF expanded greatly to counter the threat from the four neighbouring Italian territories: to the north-west, Libya, to the east Eritrea, Italian Somalia; and the recently (1936) occupied Abyssinia (Ethiopia). To accommodate the extra numbers, a new war-service battalion was formed, the Sudanese Frontier Force. In wartime, the SDF grew to as many as 20,000 men.

There were also two regiments of irregular special forces:

The British did not garrison their Empire exclusively with British troops; almost every territory had a local militia or an indigenous regular force. Prior to 1925, the garrison of the Sudan comprised a British battalion near the capital, and battalions of the Egyptian Army, both Egyptian and Sudanese, in the regional capitals.

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