John Pratt, 3rd Marquess Camden British Liberal politician (1840–1872) Parents Harriet Murray George Pratt, 2nd Marquess Camden Children John Pratt, Earl of Brecknock John Pratt, 4th Marquess Camden unnamed son Pratt Lady Clementine Pratt Siblings Lord Charles Robert Pratt Lord George Murray Pratt Partners Clementina Pratt, Marchioness Camden