The row about the proper way to interpret the history of the First World War tells us far more about the sorry state of political discourse in London than about the state of historical interpretation of the conflict.

Michael Gove, Education Secretary in the Coalition Government, has argued Britain's role in the war should be represented as a story of heroism and sacrifice in a noble struggle against German autocracy

He denounces "Left-wing versions of the past designed to belittle Britain and its leaders". He singles out Richard Evans, Regius Professor of History at the University of Cambridge, as the main culprit in this conspiracy to mislead the British public. Tristam Hunt, the Shadow Education Secretary, attacked Mr Gove's use of history to score political points as crass and tawdry and his heroic narrative of Britain's war effort as a misguided distortion. Germany, Mr Hunt insists, was not alone in pursuing policies that led to the outbreak of war. Russia, Serbia and, by extension, France, also deserve some of the blame.

His views provoked a thunderous diatribe from London Mayor Boris Johnson. It was the Kaiser's Germany, he insists, that caused the First World War. By urging Austria to attack Serbia and then declaring war on Imperial Russia, Germany launched an evil bid for European domination. Anyone who did not accept this self-evident fact was not fit to play a prominent role in politics and should resign.

The truth is that historians continue to debate the origins of the First World War and to disagree over the true meaning of the conflict.

There is general agreement that it was a war between empires. Britain, France and Russia controlled extensive empires and were defending their interests from the challenge posed by Imperial Germany. The war was, in some respects, a traditional struggle for predominance between great powers. Some scholars, most notably Prof Evans, stress the differences between Imperial Germany and Nazi Germany. He argues that Germany was, in fact, on its way to democracy and stresses that the Social Democratic Party was the largest party in the Reichstag during the war. Prof Evans also points out that Tsarist Russia was one of Britain's principal allies. This, he insists, undermines the argument that the war was a democratic struggle against absolutism.

There is some merit to this. Imperial Germany was not the same as Nazi Germany. It was not waging a war of racial annihilation in the East. Only after Tsarist Russia left the war and the United States entered the conflict in 1917 did it become easier to depict the Great War as a struggle for democracy and the rule of law. The Great War is harder to represent as an unambiguously "good" or "just" war than is the Second World War.

Yet there is considerable evidence to the contrary. Most historians agree that the behaviour of German occupying forces during the war was horrific and outstripped anything visited on the areas of Germany occupied by the Allies after 1918. Nor is Prof Evans's depiction of a progressive Germany very persuasive. The parties of the Reichstag had little or no say in the prosecution of the war until its final stages. From mid-1916 onward most key decisions were taken by what was effectively a military dictatorship.

It was only after the German armies collapsed on the western front in autumn 1918 that the Kaiser's regime turned to the democratic voices in the Reichstag. They did so because they did not want to take responsibility for negotiating a loser's peace.

The key point about these debates among historians is that they do not fall along the familiar left-right divide in British politics. They are based on contending interpretations of the same factual record. The dismal back-and-forth between politicians distorts the true state of a vibrant and important historical debate. Politicians have cherry-picked from history writing to score points. But their chief accomplishment is to demonstrate their lack of historical understanding.