This map was published the early years of the 19th century and depicts the districts of civil defence that were drawn up to counter the threat of a French invasion. The counties of England are shown grouped together into military regions and distances from English ports to the site of the ‘enemy flotilla’ are clearly shown.

The prospect of invasion by Napoleonic forces was the cause of popular alarm among the British in the early 1800s, whipped up by the dozens of tracts, pamphlets and illustrations depicting the horrors of French rule. The British government responded by quashing internal political dissent, implementing laws designed to restrict the activities of political radicals by outlawing seditious writing. This legislation was complemented by a range of ambitious engineering works designed to fortify the English coastline against French attack. Large fortified ‘Martello Towers’ were built at regular intervals along the coastline to protect the southern counties from enemy action. They were manned by volunteer forces which, by 1800, numbered some 400,000 men.