Britain's War Machine by David Edgerton – review

Britain's War Machine takes on some of our cherished national myths about the second world war. First, the image of a beleaguered but heroic island – encapsulated in "Very Well, Alone", David Low's celebrated cartoon after the fall of France in June 1940. David Edgerton calls this "one of the most misleading images in British history", noting that when Churchill spoke of fighting on "alone" he almost always referred to the British empire rather than the British Isles.

Edgerton reminds us that wartime Britain was the heart of a global empire formed by trade as much as by colonies. The outbreak of war did force global Britain to reorient its trading patterns: "near supplies" such as Danish bacon had to be replaced from outside Europe, with America becoming much more important, particularly after Japan's whirlwind victories of 1941-42, which denied Britain vital rubber, tin and oil from south-east Asia.

But Edgerton stresses the continued reliance on traditional suppliers, such as wheat and meat from Canada, Australia and Argentina, and oil from the Caribbean and the Middle East, much of it transported in British ships. Britain had the largest merchant marine in the world, and this proved vital to keep Churchill's island going until American shipping capacity developed later in the war. These imports, mostly on credit, enabled Britain to concentrate on war production rather than food supply and consumer needs.

Britain's global reach was vital on the battlefield as well. Two of the key divisions deployed against possible invasion in 1940 came from Canada; at Alamein in 1942 (now a famous "British" victory), nearly half of Montgomery's infantry were Indians, Australians, South Africans and New Zealanders. In 1945 British manpower constituted just over half the empire's fighting strength.

Britain was also a "warfare state", an "empire of machines". This fact, Edgerton argues, has been obscured by the likes of CP Snow and his view of the "two cultures" anti-technological bias of Britain's elite. Sometimes his chapters on technocrats and experts slide towards the encyclopaedic, with too much detail, but he makes several compelling points. For instance, the powerhouse of WMD development was not the universities, despite their contributions to the bomb and short-wave radar, but the big government research institutes such as the Royal Aircraft Establishment at Farnborough, and major industrial corporations such as ICI and Vickers. Again, the imperial dimension was vital: faced with a shortage of rifles in 1940, the government set up Lee-Enfield factories in Canada and Australia as well as America.

Britain's War Machine is a stimulating exercise in muscular revisionism. Yet I feel at times that Edgerton – an outstanding historian of science and technology – distorts the nature of war. Technology always matters – be it longbows at Agincourt or rifles at Gettsyburg – but ultimately battles are decided by men, not machines. Take France in 1940. German victory had less to do with overall technological superiority than the success of its surprise armoured thrust through the Ardennes and the collapse of the French command and control system.

Edgerton argues that the fall of France should be seen as having had only a "minor" impact on the British war effort compared with the south-east Asian disasters of 1941-42. Yet 1940 forced a wholesale redefinition of British strategy. Previously the government had focused on naval and air power, with France expected to bear the brunt of the land war. Edgerton insists that the British Expeditionary Force on the western front in May 1940 was highly mechanised, but to call it "a great modern army" surely misses the point. The BEF boasted only 10 divisions, half the Belgian contingent and a tenth of the French.

As 2 million French soldiers trudged off to German POW camps in June 1940, Britain had to invent a mass army almost from scratch and to teach those novice soldiers how to use their machines. Haunting memories of the Somme and Passchendaele (about which Edgerton might have said more) strengthened the determination of British leaders from Churchill down to fight a war of machines rather than men.

Yet Edgerton is surely right in his conclusion. Britain came out on the winning side thanks in significant measure to its industrial capacity and its global resources. And the British people, for all their privations, were spared the total war that ravaged eastern Europe. His book offers a fresh and provocative view of our much-loved and much-misunderstood "finest hour".

David Reynolds's books include In Command of History (Penguin).