On his death the barony of Dover became extinct, while he was succeeded in the other titles by his kinsman the second Baron Robartes, who became the sixth Viscount. He was the son of Thomas James Agar-Robartes, who was created Baron Robartes in 1869 (see below), son of Hon. Charles Bagenal-Agar, youngest son of the first Viscount Clifden. The sixth Viscount had earlier represented Cornwall East in Parliament as a Liberal and also served as Lord Lieutenant of Cambridgeshire from 1906 to 1915. His eldest son Captain the Hon. Thomas Agar-Robartes sat as Liberal Member of Parliament for Bodmin and St Austell, but was killed in the First World War, predeceasing his father, unmarried.