Mr. Allen attended Chestnut Hill Academy and graduated from Germantown Academy. He graduated from the University of Pennsylvania and served in the Army and National Guard of Pennsylvania and New York.

After spending several years at the John B. Stetson Company, a family business, where he became Vice President for Marketing, he left to become a banker with First National City Bank in New York which eventually became Citicorp. While there he became an Executive Vice President of the Industrial Credit division and twice ran the large asset leasing business. He was a prominent financier of ships and aircraft. After 14 years he left to found his own investment banking business Hunter Garrett Nicholas Incorporated that specialized in corporate finance. He also founded several other businesses including Brown Shipley and Stetson, an investment banking partnership with Brown Shipley Ltd. of London for which he was Chairman.

Mr. Allen retired from banking in 1989 and, since then, has been a fulltime volunteer as a management consultant to twelve charities in four countries. Most recently he served on the Board of Directors of the St. George’s Society of New York, Historic Royal Palaces in London and was the current Chairman of The British Society in Boston.

Mr. Allen was awarded the Freeman of The City of London. He was an Officer of The Most Venerable Order of the Hospital of Saint John of Jerusalem for which he had been Chairman of the Boston Region, a Forefather Member of Swedish Colonial Society, and a member of The Welcome Society, The Welsh Society, Mayflower Descendants, Society of Colonial Wars, Society of the Cincinnati and the St. Nicholas Society of New York. He was also a member of the Racquet and Tennis Club of New York, The Racquet Club of Philadelphia, Squadron A, the United States Cavalry Association and previously a member of the Aviation Country Club of Philadelphia.

He is survived by his beloved partner Jennifer Griffin, their dog Maddie, his son, Hunter Brooke and wife Kayla and two granddaughters, Victoria and Bailey, his son Garrett Stevens-Manning and a grandson, Britton, his son Nicholas McArthur and wife Colleen and grandsons Boden and Weston, as well as his daughter Elizabeth Helen Lewis Stetson Benigar and husband Rob and grandson Grayson. He is also survived by his brothers Frederick and Stephen and sister Elizabeth Brooke Rankin.