He served as a brigade major during the Burma Expedition and as Assistant Provost Marshal, being twice wounded in battle (once severely) and mentioned in dispatches on 22 June 1886.

[7] On 12 February, after the action at Pink Hill, Clements shortened his line in the face of the Boer advance by retreating to Rensburg siding.

After the victories of Field Marshal Frederick Roberts on the western front, the Boers retreated and Clements took Colesberg on 28 February.

[8] He was in command of forces occupying the South-Western part of the Orange Free State in March 1900, including Fauresmith, the second largest city.

[11] Slebbert's Nek was taken with little resistance and the columns joined Hunter and advanced to Fouriesburg, after which a large Boer force under General Marthinus Prinsloo surrendered to them.

[12] Clements' column moved into the Magalies valley in September and remained there for the next three months, burning farms there so effectively that the area became a "blackened desert" according to the historian Thomas Pakenham.

[3] Following the end of the war in June 1902, he held a staff appointment at Cape Town for several months,[16] then arrived home on the SS Saxon in late December 1902.

On 1 February of that year, he was sent to India as a major general in the British Indian Army to command a second class district at Agra,[18] which became the Sirhind Brigade of the 3rd (Lahore) Division under the Kitchener Reforms.