A second battalion was raised in August 1804 but remained in the United Kingdom throughout the Napoleonic Wars. The 1st battalion saw action at the Battle of Copenhagen in August 1807 during the Gunboat War. It embarked for Portugal in early August 1808 for service in the Peninsular War and saw action at the Battle of Roliça in August 1808, the Battle of Vimeiro later that month and the Battle of Corunna in January 1809 as well as the subsequent evacuation. The battalion then took part in the disastrous Walcheren Campaign in autumn 1809.