The great victory of Trafalgar had seemed to confirm for all time the crushing superiority of the Royal Navy. La Hogue, Cape Finisterre, Lagos, Quiberon, the First of June, the Nile: the list of victories over the French seemed endless. It was not surprising that for a hundred years after Nelson’s victory Britain was not seriously threatened by invasion. There were minor scares, as in 1859 when the outcry of the French Colonels over the Orsini affair raised fears that Napoleon III might seek to go one better than his great namesake against England. And in 1898, at the time of the Fashoda crisis, a veritable industry of invasion studies burgeoned among French academic and naval officers. Lacour-Gayet, Castex, Desbrières and Coquelle all wrote their studies of planned invasions of the British Isles in the years immediately following Fashoda. Coquelle indeed remarked wistfully of the comte de Broglie’s project of the 1760s: ‘it is still feasible.’

But although Britain enjoyed a century of tranquility after the almost permanent threat of invasion from 1690 to 1805, certain jeremiads began to be heard to the effect that the old system of fleet and flotilla was outmoded and would soon not be enough to guard the island shores. The full effects of the Industrial Revolution on society were now being felt. The role of government and bureaucracy increased as western society passed through the processes of industrialisation and modernisation. Warfare itself became more complex with the advent of vastly improved transport systems, especially the railways. Mass production went hand in hand with mass conscription and the mobilisation of vast armies. The control of nations’ huge war machines required more professional armies and navies. Most of all, the pace of technological change in the form of new weapons, new forms of propulsion and new methods of communication made its unmistakable impact. This was the era when men came to realise some of the awesome consequences of the Industrial Revolution – the ‘unbound Prometheus’. Above all, it was an epoch of belief in uninterrupted progress and of limitless faith in science.

Science was the nineteenth-century fetish and it was to science that those hopeful of overcoming the seemingly ineluctable British superiority at sea turned. The quest for ways and means to circumvent classical sea power became an absorbing concern of inventors, engineers and scientists, receiving its most eloquent expression perhaps in the science-fiction novels of Jules Verne (significantly, a Frenchman).

It was in 1847 that the duke of Wellington first crystallised these inchoate fears of new methods of invasion by suggesting in a famous letter to Sir John Burgoyne that the introduction of steam had opened up a new dimension in the invasion of Britain. Potential new invasion techniques had already been adumbrated during the Napoleonic wars. In the Directory period there were already rumours of a floating machine powered by wind and watermills that could convey 60,000 men and sixty cannons across the Channel in a single crossing. Pictorial representations of this behemoth, fancifully reproduced in English newspapers, portrayed it as a sort of cross between Brueghel’s Tower of Babel and Jules Verne’s later ‘Clipper of the Clouds’. Another huge raft, said to be under construction by the French Ministry of Marine in 1798, was rumoured to be 700 yards long, 350 yards wide and eight stories high. Each one of these infernal machines, it was calculated, would require the felling of 216,000 fir trees. The Gentleman’s Magazine of 1798 took up this canard and added the detail that each raft could carry men and 2,000 horses.

These machines subsisted purely at the level of fantasy and perhaps reflected deep phobias on the part of the English, and unconscious wish-fulfilment by the French nation, well aware at the conscious level that a successful descent on England came very close to impossibility.

More realistic, and therefore more serious, were the plans submitted to the Directory in 1798 by the inventor Robert Fulton. He proposed the building of submarines and the construction of underwater torpedoes. The name Nautilus, later immortalised by Jules Verne, first came to the surface in Fulton's schemes. The Directory needed more convincing. Fulton went away to the United States to perfect the first steamboat. By the time it was in running order (1807), Fulton had once again addressed himself unsuccessfully to both sides in the conflict. Ever since 1803 Napoleon had watched Fulton's progress with interest but could not be convinced of the practicability of his invention. The British at first displayed more interest, but lost their enthusiasm when a trial run of Fulton's torpedoes against the French flotilla at Boulogne proved abortive.

Fulton's later career in the United States proved beyond doubt that steamships were there to stay. The issue to be debated then became that of the implications of steamships for an invasion project. At first observers overrated the ‘technological gap’ opened up by steam. Scepticism was entertained about the defence capability of the Royal Navy, since an enemy was no longer at the mercy of wind and weather. Siren voices urged that the era of sea power proper was over. Henceforth the British Isles could only be defended once an invader had landed, by a defensive chain of forts.

Once the first panic had passed, more sober observers began to point out that nothing had really changed: sea power was still the key to political greatness. This proposition was reinforced when Europe entered the era of self-conscious imperialism. Moreover, the 'chain of forts’ idea was a non-starter. The only consequence of trying to defend behind a so-called impregnable line of fortifications would be that the enemy would contrive to get round them or would launch the attack elsewhere.

The revolutionary changes thought to be attendant on the coming of the steamship did not materialise, even though Erench strategic experts still maintained, in the aftermath of the Fashoda crisis, that this was purely through a failure of imagination. The thoughts of this new breed of fin-de-siècle Anglophobe turned to the construction of steam-driven barges, armour-plated to keep out rifle fire, and mounted with 47 mm guns to deal with the British flotilla. To the objection that this still left the problem of the heavy Royal Navy battleships, the new theorists replied that because the Royal Navy would need to steam continually while blockading, say, Brest or Cherbourg, for fear of torpedo attack, the fleet would become worn out and its men demoralised. At the appropriate moment the heavy barges could be launched.

So much for the initial hopes and fears entertained about steam. But this was not the only aspect of the new technology that worried the island defenders. At least two other contenders were brought out for sustained inspection in the nineteenth century: aerial attack and subterranean incursion. The French had been first in the field in experimentation with hot-air balloons. Apart from the Montgolfier brothers, the first crossing of the Channel by balloon was made in 1785, and Danton’s escape from Paris by this means during the Revolution had caught the popular imagination. During the Napoleonic invasion scare, the French were rumoured to be ready to build a bridge from Calais to Dover, using an array of balloons as a sort of floating crane. In the nineteenth century, as France continued to be particularly associated with this unwieldy method of flight (famously in 1870 with Gambetta's escape from the Prussian siege of Paris and in 1897 with Andrée’s ill-fated attempt to fly to the North Pole), fears grew that an entire army could be wafted over the Channel in this way.

Even more apprehension was felt over the possibility that the French could build a tunnel under the Channel. This was first proposed by the French mining engineer Mathieu in the Napoleonic period and was to surface on numerous occasions in the nineteenth century as a nightmare possibility. In 1883 a French caricature, suggesting that France could invade England by means of a Channel tunnel, gave rise to a heated controversy in England, with defence experts and railway shareholders ranged on opposite sides.

But when France and Britain came together as allies in the Entente Cordiale of 1904 – to the disgust of French pro-invasion Anglophobes who claimed to be repelled by Britain's preexisting alliance with Japan (the ‘yellow race’), the stage was set for the appearance of the third would-be invader of the British Isles. In the sixteenth century Spain had been the protagonist; from the seventeenth to the end of the nineteenth it had been France. Now there emerged potentially the most formidable of all invaders: Germany. With the emergence of Germany there was to come a new technological factor that had been barely considered in the nineteenth century: the submarine.

The rise of German sea power, one of the precipitants towards world war, raised the possibility that a lightning strike against Britain might be attempted in the event of war. Erskine Childers's Riddle of the Sands created a sensation in the first decade of the twentieth century by suggesting that preparations were being made in the waters inside Borkum for the embarkation of a large German army in shallow-draught craft which could be launched without warning across the narrow seas. The notion of a ‘bolt from the blue' became the military cliché of the hour after Lord Roberts had alerted the Committee of Imperial Defence in 1907 to the risks of sudden invasion without a declaration of war. The jittery state of nerves in this pre-World War One period sometimes had its comic side. The Secretary of State for War. R.B. Haldane, himself often accused of being 'soft on Germany', finally decided that a proper counter-espionage system was necessary in Britain as a result of a hoax. In 1908 two German tourists hoodwinked the Mayor of Canterbury into thinking they were scouting ahead for an invasion project.

In the ensuing panic in England it was at first suggested that military service in a Territorial Army force be made compulsory. so that a standing militia of 400,000 could be kept in being as a safeguard against invasion. But when it was pointed out that such a scheme would cost £8 million a year and would draw precious resources away from the Royal Navy, calmer counsels prevailed. The navy should always be paramount, it was urged: the navy's task was the preservation of the sealanes to the overseas empire and the Dominions. If this were done and imperial trade safeguarded, Britain would ipso facto be safe from invasion. In October 1908 the Committee of Imperial Defence summed up its conclusions thus: ‘So long as our naval supremacy is assured against any reasonably probable combination of Powers, invasion is impracticable . . . our army for home defence ought to be sufficient in numbers and organisation not only to repel small raids, but to compel an enemy who contemplates invasion to come with so substantial a force as will make it impossible for him to evade our fleet.’ In other words, the argument ran, a Royal Navy that was strong enough to protect British seaborne hegemony worldwide would always have the surplus necessary to deal with an invasion threat.

Interestingly, the same conclusion had also been reached by the High Command of the German Navy some ten years before. There is a supreme dramatic irony in the way Britain awoke to its potential danger ten years too late. For the very possibility raised by Childers had been spotted by German Intelligence at a very early stage only to be discarded by the Imperial Navy in the late 1890s. The Chief of Staff Rear Admiral von Diederichs wrote a lengthy memorandum in 1896, suggesting that Germany’s sole chance of success in a war with the mighty British Empire was a lightning offensive against the Thames estuary. This attack should be undertaken in the first days of such a war, in hopes of catching the British unawares and gaining strategic control of the North Sea.

This suggestion led to a veritable essay-writing contest in Berlin’s strategic circles. Diederichs’s critics pointed out that such an attack would have to be made before war was declared. If there were any obvious pointers to the outbreak of hostilities, England could easily assemble a fleet of overwhelming superiority in the Channel or off the Thames. Others pointed out that suitable embarkation ports could be obtained only if Belgium and the Netherlands were overrun. But in that case Britain would seize the Dutch East Indies; and by the terms of the 1839 treaty guaranteeing the neutrality of Belgium, France would be drawn into the conflict.

Nevertheless, the idea of a possible invasion of England continued to be broached in Berlin until 1899. The notion of overrunning the Low Countries was abandoned in favour of the conception of assembling the army of invasion in Germany’s North Sea harbours. Yet even on this scenario it was soon discovered that there were not enough transports to convey the eight army corps which no less an authority than Schlieffen considered the minimum necessary for the conquest of England. And following the jubilee Review of Spithead in 1897, when the British strengthened their Channel fleet, the prospects of a surprise attack became even more chimerical.

The coup de grâce to the already shaky German war plans for an invasion of Britain were given by Admiral Tirpitz, who in the 1890s was beginning his rise to dominance in the Imperial German Navy. Tirpitz was convinced that the only way to defeat England was to challenge her naval supremacy head-on. He regarded all ideas for a landing in England as insane, simply because the strength of the Royal Navy made it certain that the invaders would almost at once be cut off from their home base. An invasion of England had to be predicated on permanent German supremacy in the North Sea. To members of his staff who still urged the 'bolt from the blue’, arguing that Napoleon in 1805 needed just one day free from Royal Navy interference, Tirpitz replied dismissively: 'That was Napoleon’s error. If he had really succeeded in getting across and was later cut off, then both he and his army would have been lost – as in Egypt, where only flight and the premature conclusion of peace saved him from total defeat.’ As the inspiration of the newly formed German Admiralty staff, Tirpitz after 1899 turned Germany away from unrealistic ambitions of invading England towards the idea of a defensive naval policy in the Baltic approaches.

In any case other strategists were already pointing out that the submarine had radically altered the naval picture in Britain’s favour. The reasoning was that henceforth the submarine would play the role assigned from time out of mind to the defending flotilla. Even if the British battle fleet was decoyed away from the track of the invaders. Royal Navy submarines could wreak terrible revenge in the invaders’ transports. Moreover, the submarine was a much more flexible and dangerous weapon than the gunboats and cutters of the flotilla, for the threat it posed did not cease even if the invaders got ashore. It would be quite impossible for an enemy to guard his transports against submarine attack while he was landing troops. Optimists concluded from this that an invasion even on a modest scale, say 70,000 men, was impracticable in the new era.

At this stage nobody considered that submarine warfare could be a two-edged weapon, that there might be an option open to an enemy beyond that of invasion or economic blockade: cutting the lifeline of the islands by wholesale sinking of its merchant shipping. This was a later development.

The coming of World War One altered these comfortable naval perspectives. The submarine campaign alone did serious damage. This was especially true of the second U-boat campaign of 1917, which reached its peak in April that year. It became clear that the corollary to being the premier industrial nation and the leading imperial power of the nineteenth century was a greatly increased vulnerability in the twentieth, since Britain depended so much more on seaborne importation of food and raw materials.

Meanwhile the war on land threatened to make invasion a far from theoretical consideration. In October 1914 the advance of the German army through Belgium brought it to the coast. Ostend was in German hands. Immediately the spectre of invasion loomed. A descent on England could now be planned, using the self-propelled light-draught barges employed on the inland river and canal systems of Europe, plus deep-water transport from the Heligoland Bight. Although the more sanguine British strategies doubted that the numerically inferior High Sea Fleet would venture out to try conclusions with the British Grand Fleet – for a naval victory was still universally thought to be a prerequisite for the successful launch on invading transports – doubts began to arise whether the original estimate of a maximum landing force of 70,000 Germans still held good. Nervous analysts in the War Office raised the figure to a possible 160,000.

The Battle of Jutland, which ensured that the German fleet would not come out again for the duration of the war, calmed nerves and allayed fears in England. By 1917 the projected number of invaders thought likely to gain a foothold on English soil – before the Royal Navy cut them off from their supply lines and communications – was again lowered to 70,000. Even so, this meant keeping five divisions at home in England.

The war ended without serious threat of invasion to the British isles. The fact that German armies had been unable to crush the allied forces in France in the spring offensive of 1918 and thus gain possession of the Channel ports was taken as an encouraging sign. The combination of traditional British foreign policy on the continent and continued strong commitment to the navy would surely scotch future invasion plans. Yet there was one disquieting omen for the future whose force few people appreciated at the time. This was that adequate defence against an all-out submarine assault on the lifeline of the British Isles called for the extensive use of the convoy system. But this system itself drew off many of the ships that traditionally formed part of the flotilla defence. If an enemy launched a simultaneous submarine campaign in the Channel and the western approaches together with an invasion on barges, the British naval defences might be stretched to snapping point. Without an infinite number of ships, the convoy system could be strengthened only at the cost of weakening the flotilla, and vice versa. The traditional second line of defence against invaders – armed ships below the level of cruisers – could be caught between two fires by an ingenious enemy, since these British flotilla ships would have to attack the marauders in the invading flotilla and defend against submarines at the same time. Fortunately for the peace of mind of British strategists, this more far-reaching implication of submarine warfare was not seen with full clarity immediately after World War One. During 1914-18 German submarines and invasion craft had, it seemed, been securely held in the grip of the Royal Navy and its allies.

It is time to set the theme of twentieth-century invasion projects in a wider context. Nowhere is the thesis that the invasion of England is always prompted by considerations of world empire better illustrated than in the course of events before 1914. The German naval challenge to Britain, which tautened the pre-existing European tensions, was itself a belated reaction to the realisation of the importance of sea power. Imperialism, it was widely felt (following J.A. Flobson), was the motor of the prosperity of modern industrial states. In the scramble for colonies Germany had come on the scene far too late and could not therefore generate the ‘superprofits’ consequent on a world empire. The only way to make up the lost ground was to challenge the foremost imperial power on its own ground. Since the logic of a global challenge to Britain always implied ultimately a military invasion of the British Isles, it is not surprising that statesmen in London were prepared to go to war with Germany over the security of Belgium. It had been the abiding axiom of British foreign policy that enemy possession of the Low Countries spelled great danger for England.

Economic conflict, overseas empire, sea power – the correlation of these variables in causal clusters is too frequent to admit of serious doubt that this was always the underlying basis of invasion attempts against the British Isles. But the proposition has to be stated with care. In popular consciousness Marx is usually given the credit for underlining the economic motive for conflict between nations. Like many popular notions, this rests on a misconception. Marx stressed class conflict (a quite different thing) as the primary motor for intra-national conflict, with international conflict as an extrapolation or externalisation of this. The notion that it was the global struggle for economic supremacy that led nations to war was an idea much older than Marx. And the idea of a worldwide struggle for markets and outlets for surplus capital as impelling nations to war was a widely prevalent one not just in non-Marxist circles but even in anti-Marxist ones. To a large extent it was an idea that bypassed Marx himself. It was used by J.A. Hobson to explain imperialism, and much of his explanation was later taken over by Lenin. But ‘economic factor' explanations for political conflict had their most devoted exponents in the USA.

In 1913 Charles Beard produced his classic economic interpretation of the American constitution. Nearly twenty-five years earlier, in 1890, Captain A.T. Mahan argued in his classic The Influence of Sea Power upon History that global economic rivalries would eventually lead the USA into war with one of the Great Powers. His favourite candidates as America’s future enemies were Germany and Japan, and he accurately analysed the very reasons why the USA did in fact find itself at war with these two countries fifty years later. The logic of global economic rivalries, Mahan thought, would lead America into conflict with Japan over China and the Philippines and with Germany over Latin America. This is an uncanny prediction of later developments.

Mahan's ideas were most enthusiastically taken up (outside the USA) in Germany. The Germans returned Mahan's compliment by identifying the USA as their main global rival in the 1890s. From 1896 to 1901 (even longer than the ‘invasion of England' period) the German naval High Command, especially Diederichs, laid a number of far-fetched plans for landing a German army on American soil. Boston, New York and Washington were variously identified as targets. Full confidence was expressed that the small American fleet could be brought to battle and defeated. Thereafter, how could the exiguous US army, used to dealing only with Indians and Mexicans, stand in the way of the military pride of Europe, imbued with the spirit of Moltke and Bismarck?

Mahan had envisaged just such a German attack on the US east coast, precipitated by economic rivalry and implicitly supported by a neutral Great Britain, well content to see two such dangerous rivals slog it out. A modern historian describes the 1913 US War Plan Black, envisaging war with Germany (and based on Mahan’s ideas), as ‘surrealistic to the modern reader’. But it was in fact eminently logical and rational. The problem, as always, is that statesmen do not act rationally. Whether World War One really was, in A.J.P. Taylor’s phrase, ‘war by timetable’, or whether its confused origins derive ultimately from some more multi-causal version of irrationality, it was, all moral and humanitarian considerations aside, an absurd war for European nations to fight. For it was the weakening of Europe in this pointless four-year stalemate that, more than any other factor, opened the gateway to the United States, so that she emerged in 1919 as the world’s greatest power, a fact masked for two decades by American ‘isolationism’. Even when ‘isolated’ the new Colossus soon showed its strength. The Washington Naval Treaty of 1922 showed the shape of things to come. At one stroke the USA got its own naval supremacy to Japan enshrined in a formal treaty while destroying the Anglo-Japanese alliance that had lasted since 1902. At Washington the British were duped by superior cunning. In hopes of getting their war debts to the USA written off, Britain conceded the USA a free hand in the Pacific and gratuitously snubbed their old allies in Nippon – a snub that was dramatically revenged twenty years later with the fall of Singapore.

It can be seen, then, that the historical logic of the post-World War One world, after the defeat of the Kaiser’s Germany, should have meant that Germany was no longer either Britain's potential enemy or her would-be invader. With the newly established Soviet Union out of the picture as a result of civil war and 'socialism in one country’, the battle lines should have been drawn between the two giant economic blocs, the United States and the British Empire. Indeed there were many strategists in the late 1920s who felt that the next war would be between the two principal English-speaking nations, for they and they alone were in serious contention for world markets and investment. It appears that war games were drawn up in both London and Washington dealing with a hypothetical US assault on Great Britain. Such a project seemed all the more feasible in the late 1920s, for much of Ireland was now an independent republic. Given the USA’s historical support for Irish nationalist aspirations (going back to the days of the Fenians), its backing of de Valera after the Easter Rising of 1916, and the powerful and vocal domestic constituency of Irish-Americans, it did not seem absurdly far-fetched to postulate the granting of military bases in Eire for the USA. In this way the logistical problems that proved too much for Diederichs and his colleagues in Berlin when they planned a transatlantic assault on the US eastern seaboard could be overcome. US military forces would not have to operate across 3,000 miles of the Atlantic but merely across the Irish Sea. In a truly frightening sense England's danger would then be Ireland’s opportunity.

In the post-1945 world of the Atlantic Alliance it needs a leap of historical imagination to appreciate that such a scenario was by no means fantastic in the 1920s. The economic conflict of the two English-speaking power blocs, seen most dramatically perhaps in the worldwide clash between the Shell and Standard Oil petroleum companies, seemed an inevitable aspect of the future. What destroyed this neat pattern was the Great Depression and its political consequences.

US foreign policy in the inter-war years was directed at securing the ‘Open Door’ for her own products while protecting domestic industries by tariffs (the ‘closed door’ in effect); this had always been the main thrust of US economic policy in any case, ever since the Civil War. The early 1930s brought threats from three different directions. First, the British operated their own ‘closed door’, effectively sealing off the British Empire from outside economic penetration by the 1932 Ottawa agreement. Then a new aggressive and militaristic Japan demanded that China and the Far East be brought within her economic sphere of influence in the 'Co-Prosperity Zone’. Finally, and potentially most seriously of all, the USA began to be challenged in its own backyard. Under Schacht the Nazi government in Germany extended its system of bilateral trading, so successfully broached in the Balkans, to Latin America. American exporters began to be squeezed out of markets in their own hemisphere.

Franklin D. Roosevelt is rightly hailed as the architect of US economic recovery in the New Deal. But arguably his greatest economic achievement was to lift the United States from this dire three-pronged threat to a position of global economic hegemony by 1945. The clash with Japan in the Pacific was perhaps inevitable, given the premises of both sides, and especially the Americans’ determination to maintain their position in China. But the threat from the other two rivals was less easily disposed of. Here Roosevelt was immediately aided by the inept and fumbling foreign policy of Britain in the 1930s and to a lesser extent by Hitler’s inability to think through the logical consequences of his own policy.

Until the very last moment, in 1939, neither Germany nor Britain intended to go to war with each other. Suddenly in 1939 both sides found themselves in an accidental war. Since Hitler had not intended to wage war with England until 1943 at the very earliest, his war plans against his island enemy had to be hastily improvised. This is the key to the invasion project of 1940.

Roosevelt meanwhile sensed a golden opportunity to knock out his two European rivals, now conveniently at each other’s throat. Whoever won, there was one less economic rival to deal with. American reluctance to aid a beleaguered Britain in 1940, usually attributed to isolationist sentiment, was coloured at the highest levels by the perception that it would be better to let her two trade rivals exhaust themselves. When the decision was finally taken to confront Nazi Germany, as being the more formidable of the two European powers after the fall of France, American assistance was given with very tight strings attached. Article VII of the Lend-Lease Treaty, so enthusiastically hailed by Churchill, demanded as the quid pro quo for American military aid the dismantling of Imperial protection as enshrined in the 1932 Ottawa agreements. There could be no clearer indication that the Atlantic Alliance was never primarily a matter of sentiment or ideology but always of Realpolitik.

By 1941 Roosevelt's grand strategy was complete. Nazi Germany could be defeated by an alliance with the British, whose challenging position in the global economy could be devastated by Lend-Lease's Article VII, thus paving the way for world dollar supremacy (this was actually formally conceded at Bretton Woods in 1944-45). The third rival, Japan, could meanwhile be inveigled into war in the Pacific. Roosevelt’s 1941 Pacific policies virtually left Tojo and Konoye nowhere to go but Pearl Harbor. As a final piece of machiavellianism, Roosevelt decided after the fall of France to recognise Vichy France and to eschew de Gaulle’s Free French, in hopes that the dismembered French empire too would yield rich pickings to US corporations in the post-war period.

The absurdity of the accusation sometimes brought against Roosevelt – that at Yalta he betrayed US interests by his complaisance towards Stalin – can thus be seen. Roosevelt alone of the statesmen of World War Two had a vision of the post-war world that matched the real interests of the USA. Since the Soviet Union was not part of the world capitalist economy, it posed no threat to the USA as a rival for markets or investment. The possibility of harmonious co-existence between the USSR and the USA, which Roosevelt foresaw, is often overlooked by historians who see the coming of the Cold War as inevitable. As a promoter of his own country’s interests Roosevelt deserves the highest praise. Not even Churchill, rightly hailed as the saviour of his country, thought through the consequences of exhausting his empire’s blood and treasure in a titanic struggle against Germany. He saw the issue, again rightly, as a moral crusade, but nations’ destinies are, for better or worse, forged by economic Realpolitik, not morality.

Ironically, Hitler had a better grasp of this economic dimension than Churchill. Explaining his reluctance to order an invasion of England, on 13 July 1940 (three days before he issued instructions for 'Operation Sea Lion’), the Führer declared that he took the path of war with Britain unwillingly. If Britain was crushed by force of arms, the British Empire itself would fall to pieces. This would not benefit Germany. German blood would have been spilt so that other nations, principally the United States of America (Hitler’s own words), might benefit.

The foregoing explains some of the oddities of 1940. For in that year, for the first time in British history, an invasion project was launched that offended the basic economic logic that has always governed such attempts. Seen in global economic terms there was a profound antagonism between Germany and the USA, and between the USA and the British Empire. There was no such antagonism between Britain and Germany. In the 1930s the two powers with most to gain from coexistence were Greater Germany and the British Empire. The extent of Hitler’s blunder in finding himself at war with England is therefore obvious. His very improvisational skills carried him into debacle. Spoiled by luck and the ineptitude of his enemies, he trusted to fortune and his star in concocting a war policy against England on the spur of the moment. Up to June 1940 Hitler had developed no ideas on the continuation of the war against England, for according to the Mein Kampf blueprint this was not supposed to happen. Such a war did not fit into his grand design.

On the other hand, US ambivalence towards beleaguered Britain in 1940 becomes more explicable. Isolationist sentiment alone could not have prevented US military involvement in Europe if the survival of Britain had been truly perceived as crucial to the democratic ideal in the world or to US interests. In any case, US isolationism is much misunderstood. Taken really seriously it would have meant avoidance of conflict with Japan over spheres of influence in the Pacific and the embracing of the economic self-sufficiency plan proposed by Senator Robert A. Taft.

In this way, then. Britain found herself confronted by the threat of invasion in 1940 from a quarter noone ten years earlier would have imagined possible. The real point, though, which I have been at pains to establish, is that a seemingly purely military problem, arising from an exclusively European context, is seen on closer examination to be continuous with the past. The underlying factors in 1940 concerned, as all invasion attempts on these islands have always concerned, Britain’s global role and the economic implications of empire.


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