Horne was the son of Edgar Horne (1820-1905) of Witley in Surrey and his wife Maria, the widow of Thomas Everfield;[REF] his father had been head of the Prudential Assurance Company for many years,[REF] and his estate was valued on his death at £565,407 [REF].
He was married in 1886 to Margery May (died 1939), the daughter of Mr. G. A. May of Elford in Staffordshire.