Mr Johnston, 53, suffered multiple injuries during a practice game at Wellington, Florida. It is understood his horse rolled on him during a fall.

He was airlifted for medical treatment and underwent emergency surgery, but the 35-year polo veteran's head injuries were too severe.

Mr Johnston played in three US Open polo finals, as recently as 2005. He was born Summerfield Johnson III, but was only known by his nickname, Skeeter.

He spent nearly 30 years in the beverage industry, and was a former vice-president of Coca-Cola Enterprises.