Maj. Richard Harold St. Maur (pronounced "Seemer"), of Horton, Chipping Sodbury, Gloucester, (Brighton, Sussex, 6 June 1869 – 5 April 1927) JP DL was an unsuccessful claimant to the Dukedom of Somerset and briefly a Liberal Member of Parliament for Exeter, being unseated on an election petition by a single vote.
St Maur was born in Brighton in 1869, the illegitimate son of Edward Seymour, Earl St Maur, and grandson of Edward Seymour, 12th Duke of Somerset. His mother was a 19-year-old half-gipsy maid named Rosina Elizabeth Swan of Higham, near Bury St. Edmunds; St Maur's father died within months of his birth.
He was educated at Wellington College and Sandhurst, and served with the 14th Hussars and later with the Royal 1st Devon Yeomanry. He was appointed a second lieutenant in the Reserve on 21 February 1900. He fought in the Boer War at Natal with the 7th Remounts and the Royal 1st Devon Imperial Yeomanry. St Maur wrote a book which he titled "Notebook for Officers and Non-Commissioned Officers of the Yeomanry".