British anti-invasion preparations of 1803–05

In the aftermath of the French Revolution of 1789 Britain and France were at war almost continuously from 1793 to 1802, and then from 1803 to 1815, interrupted only by the brief Peace of Amiens of 1802–3 and Napoleon's first exile at Elba in 1814–15.

However both the British Prime Minister Henry Addington and Napoleon viewed the peace as temporary, and so it was, with Britain declaring war on France on 18 May 1803.

Addington's government had kept the Regular army at 132,000 men during the Amiens interlude, with 18,000 in Ireland and 50,000 in Great Britain (the rest serving abroad).

A list of men aged between eighteen and forty-five, with many exceptions (such as seamen and Thames watermen), was posted on the front of the church door.

[9] The British government had no choice—in view of Napoleon's avowed determination to invade the United Kingdom—but to rely on the patriotism of the general populace through a volunteer movement.

For my own part, I can safely aver, that I cannot see any real danger which is likely to accrue to the internal peace of the Country, when I consider the present dispositions and feelings of the people.

[13]William Pitt, in response, agreed: I am sure there is not an heart that palpitates in a British bosom that will not rouse for the common cause, and cordially join for the defence of the country.

At least I am convinced, that if any such there still remain, the portion is so small, that if armed and dispersed in the same ranks with their loyal fellow subjects, they would be converted by their example; and, like them, rejoice in the blessings of our happy constitution; like them glory to live under its auspices, or die in its defence.

On 18 August Addington issued a circular discouraging new volunteers "in any county where the effective members of those corps, including the yeomanry, shall exceed the amount of six times the militia".

[26] The response to the call to arms to resist invasion in these years has impressed some historians: "If some dissentient voices were heard in 1797–8 when the aftermath of the Revolution still lingered in the land, there was increased enthusiasm in the patriotism of 1801, and burning ardour coupled with absolute unanimity in that of 1803–5".

[31][32] A volunteer force called the Sea Fencibles had been formed in 1793; they manned small armed boats, watch and signal towers, and fixed and floating batteries along the coasts.

[33] In July 1803, the Duke of York argued for the construction of field fortifications as soon as possible because "the Erection of such Works must be immediate with a view to their probable utility", placing them at "Points where a Landing threatens the most important interests of the Country".

The Duke of York's priorities were the building of considerable fortifications at the Western Heights looking over the port of Dover and then the construction of Martello towers along the Kent and Sussex coasts.

In September 1804, Pitt's government ordered General Sir William Twiss to scout the south-east coast of England for possible sites for Martello towers, to be used as artillery emplacements.

[38] During the summer of 1804, Lieutenant Colonel Brown was sent to examine the coast to discover if flooding of Romney Marsh would be viable in case of invasion.

[39] Brown then advocated an extension of the water barrier: "...cutting off Romney Marsh from the county, opening a short and easy communication between Kent and Sussex but, above all, rendering unnecessary the doubtful and destructive measure of laying so large a portion of the country waste by inundation".

[40] The Drop Redoubt was a detached fort close to the steep cliffs, surrounded by ditches and intended for soldiers to go out and attack French infantry, built between 1804 and 1808.

[42] Another courtier wrote: The king certainly has his camp equipage and accoutrements quite ready for joining the army if the enemy should land, and is quite keen on the subject and angry if any suggests that the attempt may not be made.

[43]The King wrote to his friend Bishop Hurd from Windsor on 30 November 1803: We are here in daily expectation that Bonaparte will attempt his threatened invasion; the chances against his success seem so many that it is wonderful he persists in it.

I own I place that thorough dependence on Divine Providence that I cannot help thinking the usurper is encouraged to make the trial that the ill-success may put an end to his wicked purposes.

The Bank of England books would be sent to the Tower of London and its treasure would be entrusted to Sir Brook Watson, the Commissary General, who would transport it in thirty wagons (guarded by a relay of twelve Volunteer escorts) across the Midlands to join the King at Worcester Cathedral.

The Battle of Trafalgar, on 21 October, relieved British fears of invasion as Admiral Nelson destroyed the combined French-Spanish fleet.

[46] Captain Edward Pelham Brenton in his Naval History of Great Britain noted that after Trafalgar "another French navy, as if by magic sprang forth from the forests to the seashore, manned by a maritime conscription exactly similar in principle to that edict by which the trees were appropriated to the building of ships".