Born in 1889, the youngest of five children, who were all of normal height, Frederick, then aged 12, was leaning out of a window to get a better view of the Changing of the Guard ceremony when he lost his balance. He fell, and cracked his head on the pavement, disturbing agland inside his skull which regulates growth.
By the time he was 20, Frederick was already 7 feet, 8-and-a-half inches tall, and weighed 22 stone. He found a job as a street-lamp lighter and was also employed to pick walnuts, but his height made him an object of fascination for both children and adults. "He was a real gentle giant," said Colin Alexander-Jones, who has just finished researching a book on Mr Kempster's life.
When he stopped growing, Frederick weighed 27 stone and took size 22 shoes. His clothes were made to measure by a tailor in Scotland who marvelled at his size; his inside leg measured 60 inches, chest 66 inches and neck 18 inches.
He travelled everywhere in a special Model T Ford with no roof, allowing him to sit upright in the back. His outstretched arms had a reach of 13 feet, which made him the prized goalkeeper of the local football team.
Kempster later fell in love with a German giantess, Brunhilde, who was 4 inches taller than he was. But when the First World War broke out, Frederick was classified as a "security risk" by the Germans and was interned as a prisoner of war in Germany in 1914.
He was released two years later and returned to Britain where he settled in the West Country. But his time in a prison camp had left him weakened. He caught Spanish influenza and had to be taken to hospital - carried by eight men.
Three beds were moved together to accommodate him but Frederick succumbed to his illness and died in 1918 at the age of 29. Fourteen men were needed to lower the nine-foot coffin into the grave.
At 8 feet 4.5 inches, Frederick was six-and-a-half inches shorter that the world's tallest recorded man, Robert Wadlow of Illinois, who died in 1940.Reuse content