I fear that the French are wasting their time. The problem is that every time they look at Waterloo they say that Napoleon won on points.

Napoleon’s army was the best he had commanded since he advanced into Russia – an army of veterans, 200,000 strong. Wellington referred to his force as “an infamous army”.

My predecessor, David Chandler, who wrote the definitive account of Napoleon’s campaigns, said that the Emperor’s idea had been to get between the Prussians and the British. “I will defeat the British and the Prussians, then the Austrians, then the Russians, and Europe will be mine,” Napoleon said.

He hits the British at Quatre Bras, who go reeling north back towards Brussels, and he hits the Prussians at Lingy. They retreat east, thinking that their commander, Blücher, is dead. He is found under a dead horse and revived with gin, rides after his soldiers and turns them around.

Napoleon doesn’t know anything about this: on the morning of June 18, 1815, he is terribly complacent.

Wellington decides to fight a defensive war of attrition. Through drunkenness, stupidity or fear of their officers, the British line holds. The French have been aware for some time of soldiers advancing on their right flank. Napoleon knows that these are the Prussians, but he sends his aides out through the ranks to say they are French soldiers. He has calculated that the British will fall first and he will have time to redeploy. It is a massive miscalculation.

When the Prussians come into musket range they open fire. The cry goes up among the French: “Treason!” They think these are French soldiers that have changed sides. It is then that the French army collapses.

That is Dr Chandler’s reconstruction and it is the most telling I have ever heard. Napoleon was responsible for his own defeat: he was complacent. Wellington was anxious and left nothing to chance. And if you are going into battle it is far better to be in a state of deep anxiety, as the events of the past four years prove.

— Duncan Anderson is Head of War Studies at the Royal Military Academy, Sandhurst

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