to turn him off again like an engine", a fact demonstrated over and over again in the bloodlust unsatiated climate of much of post- war Europe. This was not simply provoked by feint surrenders, but by a desire for revenge, deliberate refusal to divert food or guards, or by orders to take no captives It also proved difficult once "you start a man killing ... But most of all there was the optimistic calculation of individual chances, as in the Tommies' song: "The bells of hell go ting-a-ling / For you but not for me" Anti-war literature was often ambiguous. Sentimental notions of soldiers as frustrated pacifists wanting to perpetuate the footie played during truces do not sit well with evidence Ferguson cites of Gordon Highlanders returning from such contacts, fingering their bayonets and muttering: "I don't trust those bastards."Lack of goodwill was evident elsewhere, namely the high incidence of killing prisoners; passages detailing these are the most shocking in Ferguson's book. Loyalty to immediate pals, or a desire for revenge, sometimes joined what Sassoon described as "an insidious craving to be killed", a fatalistic death instinct. The home front held up too, despite real privation, with far fewer strikes than those plaguing the British war effort.Whereas many British units fell apart once officers were slain, the Germans developed stochastic tactics, with tight groups of killers, who did not need constant orders, roving around the battlefields to deadly effect Nihilists such as Ernst Junger came into their element Why men endured this carnage is controversial. The exceptions included that dreary interactive gaggle of hack writers and spooks whose germanophobe scaremongering fuelled public paranoia by blurring fact and fiction.Given the huge disparity in resources between the Entente and Central Powers, Ferguson wonders why the latter were not quickly annihilated.

The human disparity was 32 to 25 million soldiers; that of combined national income 60 per cent higher in the Entente's favour, not to speak of Britain's vast reserves of accumulated overseas capital. In reality, the Germans used their slender resources more efficiently, and killed or captured far higher proportions of men than they lost. Britain could have lived with the Kaiser's European Union, while the nations of eastern Europe might have fared better under informal German empire than they did under the totalitarian tyrannies which after a brief interval succeeded it. Much of educated England had to be dragged into war screaming, shocked to find themselves allied with barbaric Russia against the land of the PhD. Hawks in the cabinet and on the Conservative opposition benches talked up Germany's rather modest initial objectives into plans for Napoleonic hegemony. By 1914, a Germany with puny invisible resources and feeble domestic revenues had lost a naval arms race with Britain, while the armies of France and Russia loomed ever larger.

This did not happen in the case of Britain and Germany, because unlike France or Russia, Germany did not threaten the Empire. Germany struck out from a sense of weakness: economic, financial and military. As Ferguson writes: "if Germany had been as militarist in practice as France and Russia, she would have had less reason to feel insecure and to gamble on a pre-emptive strike."Britain felt no obligation to defend Belgium, as the Foreign Office eagerly indicated, while nothing in Germany's initial strategic aims directly threatened the British Empire. In 1914, anti-militarism was in the ascendant, while the nations most slated to fight were forming alliances. His latest book is brilliant, hard-headed and disturbing; a pyrotechnic amalgam of war finance, kill ratios, and the gruesome fate of prisoners. It is compulsive reading.The opening scenario has some surprises. But their submarine destruction of American shipping, and fomenting of trouble in Mexico, also led Woodrow Wilson to declare war.