What if: French invasion of the United Kingdom (1803)

What if: French invasion of the United Kingdom (1803)



In 1803, Napoleon was determined to invade the British Isles. For two years, the future emperor marshaled 200,000 troops and an armada of assault craft along the northern coast of France. The success of his Armée de l’Angleterre or “Army of England” hinged on the French fleet being able to drive the Royal Navy from the sea-lanes separating the two nations, even if just for an afternoon. “Let us be masters of the [English] Channel for six hours,” said Napoleon “And we are masters of the world.”  Sadly for the Corsican conqueror, it just wasn’t meant to be – Britain’s naval supremacy was unwavering. Napoleon even briefly contemplated launching an airborne assault on England by way of massive troop-carrying balloons and rumours spread throughout the United Kingdom of French invasion tunnels being dug beneath the sea between Calais and Dover. Ultimately, Bonaparte abandoned his plans and marched his army into Central Europe instead.

But lets imagine that Napoleon manged to defeat the Royal Navy, would the British Army have a change to counter the invasion, no the British wouldn't have stood a chance.

The Armée d'Angleterre numbered 163,645 men (including the crews of the 2,000+ invasion barges) in 1804. Napoleon envisaged it reaching 200,000 by the time it would be ready to invade. The army was divided into corps: the left flank under Marshal Ney, the right under Lannes, the centre with two corps under Soult and Davout, the cavalry, and Napoleon himself. This was the French army at the peak of its power, with an organisation, doctrine and morale that no other contemporary army could match.

Against the 200,000 men of the Armée d'Angleterre, the British had only 50,000 regular troops in England — outnumbered four to one. They had another 18,000 in Ireland who might be brought over as reinforcements, but Napoleon planned to incite a rebellion in Ireland which would tie up those troops.

In addition to the regulars, there were about 75,000 militia and reserve soldiers. They had little training and no combat experience, but would have served to fill out the ranks. Their actual value in battle is questionable.

The British Army in England, even including the militia, was still considerably smaller than the army Napoleon planned to bring (125K vs 200K), as well as being far less effective. It had no permanent organisation above the brigade level, and little experience in fighting large-scale campaigns. Its performance even in small-scale landings and colonial actions in the 1790s had been patchy at best. During the Peninsular War the Duke of Wellington would turn the British Army into a highly effective fighting force, well-trained and well-disciplined with high morale; but that development still lay in the future at this point.

There was, however, another factor to consider. In July 1803 the government, perceiving the growing risk of French invasion, announced the formation of the Volunteer Corps. Something like 480,000 people had volunteered for this by 1805 — most of them were from the lower middle classes, shopkeepers and clerks and tradesmen, with members of the local gentry standing as officers. They had no military experience, no training, little in the way of discipline, and in many cases did not even have weapons; but they were keen. They were not intended to fight as organised bodies of troops, but to harass the enemy, ambush their patrols and foraging parties, and in general carry out guerrilla warfare against the invader.

These Volunteers were unlikely to have had much effect on the initial fighting, but they might have made continued French occupation of England after their victory more difficult.

Napoleon's plan was to land his 200,000 men on the north Kent coast between Sheerness and Chatham, in the Medway estuary (thus avoiding the fortifications the British had built along the south coast). From there he would mount a rapid march towards London, which he expected to reach in four days.

Once in London he would issue a proclamation announcing that he came as 'a friend of the English nation', abolishing the monarchy and House of Lords, and distributing the property of the aristocracy among the common people. He hoped by this means to stir up a popular revolution. French agents would also be inciting the Irish to rebel against the UK at the same time. Napoleon relied heavily on speed, shock and the morale effects of such a dramatic coup de main to overwhelm resistance.

He was confident that any attempt at military action by the British army after their capital had been taken could be dealt with by the French veterans under his command, but he did not make any detailed plans in advance for how to deal with this. Having put himself into a position of strength, he would improvise from there, as he had before and would again with great success. He did not expect British resistance to continue for long once their capital city with its government offices and banks and wealth and control of trade had been captured, and revolutionary spirit had been stirred up among the common people.

Whether Napoleon's beliefs about British popular opinion were correct is the only debatable point. The fact that one in five British men flocked to the colours to serve in the Volunteers or the Militia suggests that the public were not nearly as disaffected with their government as Napoleon fondly imagined. The enthusiasm for the ideals of the French Revolution that had swept the Low Countries, Germany and Italy in the wake of the advancing French armies might not be repeated in a country that had abolished feudalism centuries earlier. He could have found himself tied down in a long-term guerrilla war instead of the quick triumph he anticipated.

On the other hand, England is not Spain or Russia. Guerrilla war worked so well in those countries because the terrain is harsh. An occupying army is dependent on supply convoys because it can't live off the land, and those wagons have to stick to a small number of well-known roads through the hills or forests. Enemy raids on the roads can easily cut garrison units off from supply; the guerrillas (or cossacks, in the case of Russia) can then fade back into the mountains and swamps where the occupiers can't follow them. Southern England is mostly flat, fertile and prosperous; an occupying army can easily live off the land, and there are few places for guerrillas to hide. As such, the Volunteers might have ended up as being merely a nuisance to Napoleon rather than his nemesis.

In the end, though, it all came down to the navy.



It was by no means a sure thing that the Royal Navy would have been able to prevent a French invasion. In 1800 Britain had 127 ships of the line, the combined fleets of France, Spain and the Netherlands had 126. Note that in practice, only half or less of those ships would actually be in service at any given time; the others would be undergoing repairs or simply be laid up in port.)

So yes, Britain's navy was equal in size to the combined fleets of three other countries; but it didn't outmatch them. In terms of technology, too, British ships were no more advanced than those of their enemies; in some cases, less so. (Royal Navy captains often preferred captured French ships to British-built ones, though this was partly because the French built for speed, the British for strength, and speed is more glamorous!)

The one unambiguous advantage the British had was in training and discipline. British gun crews could load and fire their cannons about three times faster than French or Spanish crews; a skill that was due to nothing more than constant, constant practice. It's why the Royal Navy was always confident of winning any battle at one-to-one numerical odds. Still, their ships and crews were not magical; if outmatched by either a much larger ship or greater numbers of enemy ships they would still lose. With the overall odds so finely balanced, it would only take bad luck on the British side or good planning by the French for a smaller British fleet to run into a larger French-Dutch-Spanish fleet and be overwhelmed, and then the balance of power would tilt irrevocably.

Napoleon's plan was for the French Mediterranean fleet to combine with the Spanish fleet. It would then lure its British counterpart across the Atlantic to the West Indies by threatening an invasion of Britain's Caribbean colonies, only to double back and return to Europe unexpectedly. Here it would link up with the French Atlantic fleet and the Dutch fleet, and together they would overwhelm the British Channel Fleet. By the time the Mediterranean Fleet realised its mistake and sailed back to Europe, the Channel would be under French-Allied control and Napoleon would be sitting in London.

There's no reason why this plan wouldn't have worked, except that Nelson (in command of the British Mediterranean fleet) wasn't fooled for long and returned straight away; while the French and Spanish Combined Fleet didn't follow through with the plan and link up with the French fleet in Brest, but just returned to Spain by itself instead. (By that time Napoleon had called off the invasion of England anyway, due to Austria and Russia declaring war on him as well.) But a less dynamic and capable British admiral, or a more aggressive French one, could have turned the campaign into a French victory.

Napoleon certainly wouldn't have had any problem crossing the Channel with his army if the British fleet was defeated. He'd spent over a year mobilising ships and barges for the invasion, including hundreds of new gunboats specially built all over France for this purpose. He was far better prepared in 1805 than Hitler was in 1940.

Article was posted on Quora and was called: How well would Napoleon's planned Invasion of Britain go if he managed to successfully land his entire Army of England on British soil?