Ivan was educated at Haileybury College, and at St Thomas’s Hospital Medical School, qualifying M.B., B.S. in 1906, and M.D. three years later. He subsequently filled the posts of assistant in the x-ray and in the children's surgical department at St. Thomas's; of house-physician to the Brompton Consumption Hospital; and of anaesthetist to the Royal Ear Hospital, Soho. He then settled into practice at Knightsbridge, holding the appointments of anaesthetist to the Golden Square Hospital, and of honorary medical officer to the Actors' Association. He was described as a keen musician. Ivan volunteered for service with the R.A.M.C. as soon as war broke out, taking a temporary commission as lieutenant on 19th August 1914. He was attached for three years to his father’s old regiment, the Rifle Brigade. In May 1915, he was awarded the Military Cross for tending the wounded under fire at Neuve Chapelle, and a bar to the Cross at the battle of the Somme “For conspicuous gallantry and devotion to duty. He tended and dressed the wounded continuously throughout the operations under very heavy fire, displaying great courage and determination.” He won the Distinguished Service Order at the battle of Ypres “For conspicuous gallantry and devotion to duty in clearing the wounded. He took his stretcher-bearers well in advance of our forward positions and behaved with the most exemplary courage and devotion throughout, sparing no effort to collect the wounded men. After his battalion was relieved he continued to work under the heaviest fire for another twenty-four hours, and was severely wounded on his way back after all the cases had been cleared. He set a splendid example of energy and devotion to duty.” Ivan was severely wounded in the jaw, but was able to return to his regiment in January 1918. He was taken prisoner on 24th March, dying ten days later of his injuries in a German hospital. Ivan was the son of Major General H J Maclean (Rifle Brigade) and Frances Maclean (nee Clarkson).