A contemporary description records that 'there were few more glamorous young men in Society than 'Archie'. His good looks, charm, and romantic Highland aura were spiced with a touch of daredevilry ...' Sinclair was a life-time associate of Churchill and a dedicated Liberal committed to 'Home Rule' for Scotland. He did much to ensure the continuing life of the Liberal party as its numerical strength dropped between the two World Wars. Like Churchill, he opposed appeasement of Hitler and served him throughout the Second World War.