Antonia Fraser has been awarded the Biographers' Club prize for Lifetime Services to Biography.
Fraser has written several biographies of historical figures, including her 1969 biography of Mary, Queen of Scots, and studies of Cromwell, Charles II and Marie Antoinette.
Lady Antonia, the widower of playwright Harold Pinter, said: "I have always been fascinated by the whole subject of historical biography, both as a reader and a writer: so this award is dear to my heart, as well as a great honour."
Previous winners of the award include Michael Holroyd in 2009, Philip Ziegler in 2010, Seline Hastings in 2011 and Claire Tomalin in 2012.
The prize will be presented to Lady Antonia at the Biographers' Prize Dinner on 20th November. The dinner will also see the presentation of the £5,000 HW Fisher Best First Biography prize, and the £2,000 Tony Lothian prize for proposals by first-time biographers.
The HW Fisher shortlist is In Two Minds: A Biography of Jonathan Miller by Kate Bassett (Oberon); Cosmo Lang: Archbishop in War and Crisis by Robert Beaken (IB Tauris); This Boy by Alan Johnson (Bantam Press); Margaret Thatcher: Not for Turning by Charles Moore (Allen Lane); Tarantula's Web by John Smart (Michael Russell); and Everest: The First Ascent by Harriet Tuckey (Rider/Ebury).