Joseph Thompson (1778-1855), founder of the famous dynasty of Bridgwater ironmongers, was the maternal uncle of John and Thomas Clark. His son, Francis James Thompson (1813-1896) was active in the Temperance movement, and took part in the revival meetings organised in the town by the Earl of Cavan, and Baron Radstock, and was active in the campaign to repeal the Contagious Diseases Act. He was involved in the establishment of the Free Library and the Bridgwater School, Board. He was mayor in 1883 and subsequently alderman and a member of Somerset County Council. His grandson, William Thompson (1837-1927) was active in education in the town From 1882 is served on the School Board, and later was chairman of the Borough's education committee. He was alderman in 1901 and mayor in 1912, and was a JP.
His great-grandson Harold Stuart Thompson (1870-1940) studied at Sidcot and Bootham schools, excelling in botany and physical geography. He devoted his life to the study and collection of wild flowers, and toured extensively throughout Europe, particularly Switzerland, in order to obtain specimens. He was Honorary Secretary of the Watson Botanical Exchange Club, an associate of the Linnean Society, and a member of University Court at the University of Bristol. He died on March 3, 1940, aged 69. He was buried at Wembdon Road Cemetery in the family grave.