After serving in Malta and India, he became Assistant Adjutant General at Home District in 1893. After the outbreak of the Second Boer War he was appointed Colonel commandant of the City of London Volunteers who proceeded to South Africa. This corps included infantry, mounted infantry and artillery. They were in South Africa from January 1900 until October 1900, returning to England. The corps was disbanded in December 1900. MacKinnon was awarded with the Knight Grand Cross of the Order of the Bath and Knight Commander of the Royal Victorian Order.Individual image from photographed poster of tobacco and cigarette cardsmalta, india, assistantadjutant general, second boer war, city of london volunteers, colonel, south africa