After taking an honours degree at Magdalen College, Oxford, Macnair spent 12 years in industry before joining a stock-broking partnership. He retired in 2000, enabling him to devote more time to writing, lecturing, golf, travel and photography. His biography of the railway pioneer William James (1771-1837) The man who discovered George Stephenson was published by the Railway & Canal Historical Society in 2007. He also edited his mothers letters from the early months of the Spanish Civil War (Witness to War, Brewin Books 2007). He and his wife have lived all their married life in Warwickshire.