The Sea Fencibles were a naval militia established to provide a close-in line of defence and obstruct the operation of enemy shipping, principally during the French Revolutionary and Napoleonic Wars. The earliest recorded use of the term was in 1793, when Royal Navy captain Sir Home Popham organised groups of fishermen to guard against French vessels off the coast of Nieuwpoort, Belgium. At Popham's suggestion the British Admiralty subsequently authorised the formation of co-ordinated Sea Fencible units along the English and Irish coasts, supported by a network of Martello towers. Popham's Sea Fencible companies consisted of merchant seamen using their own private or commercial vessels, but operating under letters of marque that authorised them to capture enemy ships should opportunity ari