It so happened that, in the autumn of this year, Britain’s new Liberal-Conservative coalition government began to plan 10 to 20 per cent cuts in its £37billion defence budget at the same moment as the country celebrated the seventieth anniversary of the Battle of Britain (August-October 1940).

For the authorities, the timing of these two things was unfortunate. First, in unprecedented style, debate about whether to maintain Trident, the country’s strategic nuclear deterrent, had forced itself into official circles, causing real divisions. But what was worse was that the main service singled out for swingeing cuts was the Royal Air Force – just the body of armed men whose worth, seven decades after it had repulsed the Luftwaffe, appeared incontestable.

The coincidence has already proved revealing. Sir Stephen Dalton, the Air Chief Marshal, has felt compelled not just to seek support for his service by harking back to the Battle of Britain, but also to make a special plea in support of the relevance of air power to today’s and tomorrow’s conflicts. Dr Christina Goulter, from the highly regarded defence studies department at King’s College London, has made a similar plea, attacking what she calls ‘the widespread perception of Afghanistan being all about “boots on the ground”, and that “war among the people” is the only type of scenario we need to focus on for the foreseeable future’.

That military leaders and experts feel called upon to uphold the importance of control of the skies, so long after the Second World War confirmed this, shows that they are not sure of themselves. In this contemporary context, Richard Overy’s book The Battle of Britain: Myth and Reality, first published in 2002, helps throw today’s uncertainties into sharp relief.

Overy rightly notes that Britain was not united behind a policy of fighting on after Dunkirk. The foreign secretary, Lord Halifax, certainly wavered. Other figures, such as the military strategist Basil Liddell Hart, the liberal Tory ‘RAB’ Butler at the Foreign Office, and David Lloyd George, Britain’s ‘outstanding leader’ in the latter years of the First World War, all favoured a policy of negotiation with Hitler. Nevertheless, the resolve to fight in 1940 was strong, and supplies a vivid contrast with the vacillation about Britain’s role in the world that characterises the country today.

Overy carefully reviews the revisionist myth that Hitler never planned to invade Britain in 1940, and just as carefully rejects it. There were strong German doubts about the desirability and feasibility of invasion, and it was fully apparent to Hitler that invasion would be no picnic. Germany, familiar with continental conflicts, knew, in the words of one of its generals, ‘literally nothing’ about amphibious operations. Importantly, Hitler and his top brass discussed a massive campaign against the Soviet Union at a conference as early as 31 July 1940: German imperialism had both Britain and Russia in its sights. Still, if the RAF could be eliminated, Hitler, ever the opportunist, would have had a go.

Overy’s is a balanced, spry and often delightfully laconic assessment of the Battle’s historical significance. His book is balanced partly because he is a brilliant historian, but also because, as he says, the British and German forces were, in a great many respects, ‘remarkably matched’: indeed, at the end of the Battle, neither side was defeated ‘in any conventional sense’. In fact, the Few were not so few: nearly 3,000 British and Allied pilots fought. More than 550 were killed.

The Few were not so few: nearly 3,000 British and Allied pilots fought – more than 550 were killed

Britain had more pilots of single-engine fighters available for battle than Germany throughout the three months of combat. Also, the British aircraft industry out-produced German aircraft factories throughout the period. Britain’s Hurricane fighter, which was directed at German bombers, and its very much smaller numbers of Spitfires, directed at enemy fighters, were ‘at the cutting edge of fighter technology’. These two machines could out-turn Germany’s Messerschmitt Me 109 fighter. Though good high up, the Me 109 had a range that could only get it as far as London.

German bombers were more backward still. The German tactic – to send out those bombers in the hopes that its fighters would be able to destroy British fighters taking the bait – was always dubious. On top of radar, which was critical to Britain’s success even if it did not yet work on land, London had better intelligence, since it could determine the German order of battle from decoding the Luftwaffe’s ‘Enigma’ communications traffic. Also, Britain was fighting on home ground.

The mythology about the Few is still remarkable. Churchill himself came up with the phrase in a weak speech on 20 August, in which he gave far more attention to the campaign against Italy in Africa, and to Bomber Command, than he did to Fighter Command. In Overy’s view it was an Air Ministry pamphlet, Battle of Britain, published in March 1941, which gave the encounter its legendary dimensions. Running to 32 pages, Battle of Britain sold a million copies at home and was also distributed in the US and the Dominions.

Today, some still want to suggest that the Battle preserved not just Britain, but the whole of civilisation. The judgment that Overy makes on his last page – that ‘no one pretends that the Battle of Britain decided the war’ – is therefore a little hasty. In his preface, though, Overy says that a British ‘abdication’ in 1940 would have been a calamity for the world as a whole.

Perhaps. It would certainly have been a calamity for the British Empire. But was the Empire saved by the RAF a zone of civilisation? Nobody should underestimate the difference between living under Nazism and living under, say, Churchill. But the Empire was a zone of naked British self-interest, just as much as conquest was a rational strategy for a late-arriver imperialist power like Germany. Britain’s wartime conduct in the Indian subcontinent alone shows that it could be as insouciant about enormous numbers of civilian deaths as Germany.

Overy does note that Labour leader Clem Attlee took charge of getting Britain’s stock of poison gas up to the 2,000 tons agreed before the war. However, he is adamant that Britain, like Germany, never had a policy of using its air force ‘to mount terror attacks for the sake of pure terror’. Well, let us leave aside, just this once, Britain’s incineration of thousand upon thousand of civilians in Hamburg and Dresden. What, though, about Hiroshima and Nagasaki? It was America that dropped the Bomb, but, as prime minister after Churchill, Clem Attlee fully connived with the decision to use unprecedented, atomic terror to get Japan to surrender.

To his credit, Overy makes the point that perhaps the most enduring myth of Britain’s conduct after Dunkirk was that it fought alone. It is however striking that, though he recognises the role of Britain’s Dominions and colonies in the war as a whole, he puts the Empire in brackets early on in his book and then bothers with it very little.  Some amusing passages about British fears of an alliance between Germany and the IRA detain him more.

Today Britain has no Empire to defend. What current controversies about cuts in defence also reveal is that the military no longer can be sure that they can rely on a political climate in which brave men would risk a significant death count to defend, with popular support, a nation and a culture – still less an Empire – they believe in.

The Battle of Britain was a key episode in a conflict between two empires: Britain’s, which was well established but set for long-term decline, and Germany’s, which was mostly created by the conquest of nine nations in Europe. The Few were quite numerous, but they showed more dedication and willingness to engage in self-sacrifice than might ever be possible in Britain today.