 He also took part in the Battle of Luchana, an operation to defend the Port of Bilbao on the north coast of Spain, during the First Carlist War.Maitland also fought at various battles during the First Opium War including the Battle of Canton at which he commanded the 1st naval battalion.He gave evidence to the Royal Commission on the Defence of the United Kingdom and argued that building powerful ships was more important than building fortifications.