Dyke, Sir William Hart (1837–1931), MP, Conservative party chief whip, chief secretary for Ireland, and pioneer in lawn tennis and squash, was born 7 August 1837, second son of Sir Perceval Hart Dyke, of Lullingstone Castle, Kent, and his wife Elizabeth, daughter of John Wells of Bickley Park, Kent. After a short private education he attended Harrow School. At Oxford he was an outstanding athlete and representative rackets player. In 1860 he challenged the current world champion and won the title, as an amateur, over two matches (the only non-professional titleholder ever in the sport). With a number of fellow players he brought about the evolution of rackets/fives into modern close-court squash during the early 1860s. He was nearly as skilful at the early game of tennis: it is accepted that he and two friends originated the rules of lawn tennis (as taken up by the All-England club at Wimbledon, in the summer of 1873) at Lullingstone Castle, where the first match was played. All told, his political career was less distinguished. Reluctantly setting aside the hope of joining the Royal Navy on graduation from Oxford, he took the advice of his father and successfully contested the constituency of West Kent in 1865, uninterruptedly holding one or other of the county constituencies till 1885. Regarded as good-looking, popular, and a practical and sensible speaker, he became a close friend before long of Benjamin Disraeli. Made party whip in 1868, he was promoted to chief whip for the duration of the conservative government of 1874–80, and appointed joint secretary of the treasury. He succeeded to the baronetcy in 1875.
Exhausted and ill during late 1879, he was blamed in some quarters (after conservative defeat in the 1880 general election) both for party disorganisation in the constituencies, and for the unfortunate timing of government dissolution. However, in June 1885, after the conservative return to government, he was made chief secretary for Ireland by the marquess of Salisbury (1830–1903) that month; he had been elected MP for Dartford (1885–1906). The home rule party had, unusually, been consulted in the matter and given cautious acceptance to his nomination. By August 1885 he had supervised the passage into legislation of the Ashbourne land act, which very significantly advanced the prospect of an Irish peasant proprietary. In this instance the chief secretary was, however, overshadowed in political importance by the lord lieutenant, the 4th earl of Carnarvon (qv) (d. 1890). Hart Dyke's tenure of office ended with the collapse of the Salisbury administration in January 1886. During Salisbury's second administration (1886–92) he worked on the development of state educational policy, ushering the free education bill of 1891 through the house of commons. Retiring from parliament after failing to get reelected in 1906, he remained active in county business till 1909. He died 3 July 1931 at Lullingstone castle, where he is buried.
He married (May 1870) Lady Emily Caroline Montagu (d. 1931), elder daughter of the 7th earl of Sandwich; they had two sons and three daughters.