Sir Walter Buchanan Riddell was a Judge and 10th Baronet of Riddell, Roxburghshire. He was succeeded by his nephew John Walter Buchanan Riddell, a barrister, the son of his younger brother, Rev. John Charles Buchanan Riddell. His youngest brother was Charles James Buchanan Riddell (b. 1817) who served in the Indian Mutiny campaign in 1858. In 1859 he married Alicia Ripley, daughter of William Ripley.
In 1874/1876 Riddell's name was included in a list by JW, that may have been a guest list for the private view of JW's Pall Mall exhibition of 1874 or a subscription list for JW's Venice etchings, as proposed in 1876 [#12714]. His address at that time was 6 Princes Gardens.
Debrett's Peerage, Baronetage, Knightage and Companionage, London, 1896.