Montgomery entered business, working for Yardley and several other companies, building close links with Latin America. He has served as a patron and chairman of various Anglo-Latin American organisations, including the Anglo-Argentine Society, Canning House and the Hispanic and Luso Brazilian Council. He succeeded in the viscountcy following his father's death in 1976 and originally sat as a Conservative in the House of Lords until 1999, when he and most other hereditary peers were removed from the House under the House of Lords Act 1999. He was returned to the Lords as a crossbencher in an election of hereditary cross-bench peers in 2005, following the death of Baroness Strange.
^ abcdPeter W. Hammond, ed. (1998). The Complete Peerage or a History of the House of Lords and All its Members From the Earliest Times, Volume XIV: Addenda & Corrigenda. Stroud, Gloucestershire, U.K.: Sutton Publishing. p. 775.