He was born in 1907 and grew up at Newbay House, Co Wexford, Ireland, the home of the Jefferies family, his maternal grandparents.
[1] During the Second World War, he was awarded the Distinguished Service Order for gallantry whilst serving as a Captain in the 12th Lancers during the Dunkirk evacuation.
He commanded his squadron 'with the greatest dash and energy so he obtained much invaluable information'.
[2] He was awarded a bar to his DSO for command of 27th Lancers in the closing stages of the war in Italy.
Horsbrugh-Porter later achieved the rank of lieutenant-colonel and helped establish the 27th Lancers (known as 'Porterforce') and, this amalgamation of various units, were active in the liberation of Italy most notably at Ravenna.