[8] The Scottish Horse was a Volunteer Force regiment raised in 1900, with drafts from Australia, Scotland and South Africa.

When the regiment was disbanded later in 1902, he was given command of the Natal Militia, with the rank of a brevet lieutenant colonel in the South African Honours list published on 26 June 1902.

[10] Leader returned to the United Kingdom on the SS Kildonan Castle in August 1902,[11] but was soon back again in South Africa to take ups his command in Natal.

[5][14] Leader stayed on the half-pay list until June 1911 when he was appointed to the staff of the 2nd (Rawalpindi) Division of the British Indian Army.

[16] In the First World War, Leader took his brigade to the Western Front in France, serving with the 1st Indian Cavalry Division.

[17] Then in February 1916 he was given command of the 1st Indian Cavalry Division, with the temporary rank of major general,[18] which in January 1917 became substantive.