Riddell was commissioned in 1798 and took part in the
Battle of Copenhagen in August 1807 during the
Napoleonic Wars. He became a
major in
50th Regiment of Foot on 12 December 1807 and transferred to the
79th Regiment of Foot on 21 April 1808. He became permanent assistant at the Quartermaster General's Department on 4 January 1810 and then went to Spain as Assistant Quartermaster General on the staff in November 1810. to 1852. Riddell is buried in
Greyfriars Kirkyard in central
Edinburgh. ==References==