The advent of steam power in the 19th century raised the fears of invasion. Ships could now cross the Channel with certainty and seize some undefended harbour or river mouth, land an army, and establish secure communications with France. The response to these fears was the construction of fortifications at a great cost while the Navy was allowed to dwindle. The fear of invasion had clouded the problem of defence facing Britain. Defence was now seen to be wholly in terms of invasion. The fact that the maintenance of communications was essential for defence, and that a strong Navy was essential for this, seemed to have been forgotten. This position would be reversed in time, largely due to Haldane and Fisher in the 1900’s.
Not all agreed with fortifications. Lord Dundonald, in words that could have been written in May 1940, stated in 1862: “Immovable stations of defence, as a protection against invasion, are not only costly and of doubtful utility, but a reliance on them is, in my mind, an indication of a declining State. It is little short of imbecility to suppose that we erect great imposing fortifications an enemy will come to them when he can operate elsewhere without the slightest regard to them; and the more so as the common experience of warfare will tell him, that numerous fortifications are in the highest degree national weakness, by splitting into detail the army which ought to be in the field against him, but who are compelled to remain and take care of their fortifications”.
The focus was still on fortifications when the Coast Defence Committee was set up in 1870 to report on the Martello Towers and Coast batteries of Suffolk, Essex, Kent and Sussex. The Committee was tasked with reporting on the state of coastal defences in the light of modern weapons. Although the Committee was not assessing the possibility of invasion in detail, it did give some opinions on this as the background to the report. The opinions expressed remained largely unchanged up to the outbreak of WW1. The Committee drew largely on the conclusions of the 1859 Royal Commission on the Defences but recognized that the improvements in heavy armour in ships and in heavy guns and the advent of steam power all increased the risk of an invading force reaching the coast.
Right - Martello Tower, Shingle Street with a WW2
defence structure constructed on top!
The problem of defence of the coast line was as relevant then as in WW2. If troops were deployed in small detachments defending the coast Line, this would take up a sizeable portion of the Army while also scattering the Army’s strength. On the other hand, the fact Britain was an island was its greatest defence against invasion – it would be foolish to neglect the defence of the most powerful bulwark which nature had endowed us with.
London was assumed to be the main objective of any invading force. The closer to London of a suitable landing-place, the more attractive it would be to an enemy. Viewed form this aspect, the coast between Selsey Bill in Sussex to Orfordness in Suffolk was deemed to be at the greatest risk, being three to five days march from London.
Although the network of railways provided the means to rapidly concentrate troops at the threatened part of the coast, any invasion would likely be of a surprise nature and the enemy may disguise their intention with feints. Hence the Committee recommended that powerful guns, sited to cover favourable landing-places and secured in defensive enclosures so they could hold out until relief troops could arrive was the best way of defending this stretch of the coast. These guns could be supplemented by mobile pieces held in depots and deployed in times of emergency.
The defence of ports was also considered of great importance. An enemy may want to disrupt the coasting trade by attacking these ports but more importantly the possession of a harbour by the enemy during any invasion attempt would enable the enemy to maintain communications and the supply of his forces. The Committee recommended that such ports should be defended as permanent forts.
The Committee noted that many of the existing defences were obsolete, with old muzzle loading guns and not a single gun that could deal with the modern ironclad ship. The recommendations of the Committee was an upgrade of existing defences and the construction of new batteries for light guns in earth works, intermediate between the permanent forts, to guard suitable landing places but acknowledged that such works need not be started until a period of apprehension. In Suffolk, the recommendations consisted of improving magazines and thickening the walls of the Martello Towers and the construction of new heavy batteries at each end of Orfordness, both to cut off the peninsula and protect Aldeburgh and Hollesley Bay. It was recommended that Shotley Fort should be upgraded to be the key to the defence of Harwich Harbour while Landguard Fort should only be held as an advanced battery.
Due to cost and the improvement of modern weapons, most of the Committee’s recommendations were not carried out. However further fortification works did continue with the construction of the redoubts of the London Defence Positions in the 1880’s. Prior to the Committee reporting, the decision to upgrade Landguard Fort had already been taken but its muzzle loading guns were obsolete within five years of being installed with the adoption of breach loading guns. New work was required to convert the existing defences to take the modern breach loading guns but was expensive, and progress at modernising the defences slow. The modern guns were much more effective than the old rifled muzzle loading guns, requiring much fewer guns. Haldane was to dismantle most of Britain’s obsolete Coastal defences and those of London, amounting to some 300 guns employing 2,000 gunners as part of his reforms.
It is of interest to note the views a French writer in the spring of 1899 following the Fashoda crises. He noted how an invasion of England might be undertaken and was convinced it would be successful.
Steam power now meant the Channel could be crossed with certainty. He considered a barge type of vessel drawing less than a metre of water and capable of carrying up to a company of infantry with a speed of eight to ten knots was needed. The sides of the barge would be armoured against rifle fire and be provided with a Q.F. 47mm gun. A flotilla of 1,500 such barges would transport an army of 150,000 to 175,000 men.
He thought the British fleet could be prevented from destroying the barges during the crossing. If the barges were assembled on the French coast, the British ships would be forced to continually patrol, being at the risk of torpedo attack. A series of feints, attacks by torpedo craft and also moving the barges between various French ports at night would both confuse and wear out the British fleet. At a favourable moment the invasion fleet would put to sea, timed to arrive at the landing beaches at high tide. Troops could be landed immediately, covered by the 47mm guns while as the tide ebbed artillery etc could be unloaded from the barges.