Canning was the dominant figure in the cabinet and directed the seizure of the Danish fleet in 1807 to assure Britain 's naval supremacy over Napoleon .
Canning was Foreign Secretary ( 1807 -- 09 ) under the Duke of Portland , who was ill .
Foreign Secretary was the dominant figure in the cabinet and directed the seizure of the Danish fleet in 1807 to assure Britain 's naval supremacy over Napoleon .
Canning was Foreign Secretary ( 1807 -- 09 ) under the Duke of Portland , who was ill .