Early in the war, Colonel Robert Baden-Powell improvised searchlights to deter night attacks during the Siege of Mafeking. Soon afterward a detachment of the Electrical Engineers Volunteers went to South Africa where they operated electric Arc lamp searchlights, the first use of such equipment by the Royal Engineers on campaign. Leaf was granted the temporary rank of Captain in the Army on 17 March 1900, and served with detachment, which was in South Africa from April to October 1900 in the Transvaal and Orange Free State.
This sequence of events took place early in the war when Colonel Robert Baden-Powell devised makeshift searchlights to counter nighttime attacks during the Siege of Mafeking. Following this, a detachment of Electrical Engineers Volunteers was dispatched to South Africa where they utilized electric arc lamp searchlights, representing the first instance of such equipment being employed by the Royal Engineers in a military setting. Leaf received temporary Captain status in the Army on 17 March 1900 and served with the detachment which operated in South Africa from April to October 1900 in the Transvaal and Orange Free State.