‘Hold your ground!’ the colonel of the battalion bellowed to his men. ‘For England!’

Arthur watched a squadron of cuirassiers swing towards the square, their gleaming breastplates shimmering as their mounts stretched their necks and galloped down the gentle slope.

‘Fire!’ the colonel shouted and the view of the enemy was obliterated by smoke. Arthur heard the thud of the bullets impacting on horseflesh, and the clatter as they struck the cuirassiers’ breastplates. The smoke eddied away revealing horses and men strewn across the flattened crops.

‘Fire at will!’ the colonel ordered.

On all sides now the first volleys blazed out and enemy cavalry tumbled to the ground. Then they were in amongst the squares, flowing between the rows of bayonets, like a wave crashing against rocks and forced to channel its flow between immovable obstacles. The most fearless of the cavalry steered their mounts up to the lines of bayonets and then attempted to lean out and slash their blades down at one of the kneeling men. But, almost to a man, they were shot out of their saddles before they could strike.

As Arthur watched he nodded with satisfaction. His men were holding firm, and as long as they did, the French cavalry would be sacrificed to no purpose. The only anxiety Arthur had was that while his infantry was preoccupied, Bonaparte might be ordering up infantry and artillery to support the attack. If that happened then there was little that could be done to save the allied army. Threatened by cavalry they would be forced to remain in square, and thus provide perfect targets for the enemy’s cannon.

His train of thought was broken as one of his aides was thrown to the side by the impact of a bullet. With a groan the young officer fell from his saddle.

‘Get him to the dressing station!’ Somerset ordered a passing drummer boy, and the wounded officer was dragged away, towards the colours where the other members of the battalion’s band were treating the injured.

Some of the Frenchmen had realised the futility of trying to break into the squares and had sheathed their blades and taken out their horse pistols to fire at the infantry who had defied their initial charge. The last of the volleys had been fired and now the air was filled with a constant crackle as individual soldiers reloaded and fired. The smoke hanging over the squares was soon as dense as the thickest London fog and the enemy horsemen were little more than shadows. The bloom of muzzle flashes lit up the smoke all around, and above the sound of gunfire Arthur could hear the desperate cries of officers of both sides encouraging their men, as well as the cries of the wounded and the terrified whinnies of crippled horses.

For fully twenty minutes the enemy cavalry attempted to break into the squares, but each time one of Wellington’s men fell the body was dragged inside the square and the gap closed up and the formation remained as impregnable as before. Then Arthur was aware that the fire was fading away, and a voice cried out,‘They’re going! The Frogs are on the run, boys!’

A cheer went up, and spread from square to square. Arthur gestured to his staff to follow and trotted out of the square that had sheltered him, the infantry moving aside to let him by. He cupped a hand to his mouth and called out, ‘Gunners to your pieces!’

Passing out of the smoke, he rode forward a short distance to gauge the situation. A handful of the enemy were still retreating over the ridge, and those who had lost their mounts struggled across the churned field, hampered by their heavy boots and cumbersome breastplates. Hundreds more were sprawled on the ground with their mounts, many writhing feebly as they groaned. The artillery crews paid them no attention as they dashed forward and manned the waiting guns. Not one of the guns appeared to have been spiked, Arthur noticed in surprise. A foolish oversight on the part of the enemy, and one for which they would pay dearly. He headed across the slope to join the battery of Captain Sandham. His nine-pounders and howitzer were in action as Arthur rode up and acknowledged his salute.

‘Pound ’em, Sandham.’

‘I will, your grace,’ the captain grinned.

Two hundred yards away, the French officers were struggling to rally their troops and Arthur recognised Marshal Ney wildly haranguing the men before him. Suddenly the marshal’s horse lurched as a roundshot smashed into its neck. The animal collapsed beneath Ney, but as Arthur watched he calmly rose from his saddle and strode a few paces to the nearest horse, took its reins and ordered the rider to get down. Once in the saddle of his new mount Ney continued his impassioned address.

‘They’re coming again!’ Mercer yelled.

‘Get back to the squares,’ Arthur ordered. ‘You too, Somerset.’

Sandham’s crews fired their last rounds and made off. Arthur waited a moment longer, then reached for his telescope and trained it on smoke rising up from a village away to the east, no more than two miles from where he stood. There was fighting there, and there could be only one explanation for it - the first of the Prussians had reached the battlefield. A French bugle sounded the advance and Arthur snapped his telescope shut and turned Copenhagen back towards the squares dimly visible in the slowly dissipating smoke.

The next charge suffered the same fate as the first and then the attacks became piecemeal as each enemy regiment broke off, rallied and came back again. During the intervals between the attacks, the French artillery opened fire and the shot arced over the ridge before plunging into the densely packed squares, causing far more casualties than the cavalry attacks. Arthur rode from square to square to show his presence and encourage his men.

‘Heads up, lads, they will not break us! . . . Just a while longer, now . . . The Prussians are coming!’

The men took heart from his words and shouted their scorn at the enemy as they returned again and again, stopping their tired mounts within pistol range and hurriedly discharging their weapons before trotting away to reload. As the smoke cleared before the face of one of his squares Arthur saw a French officer standing by one of the abandoned guns venting his enraged frustration by raining frenzied sword blows on its barrel.

At length Ney must have realised the futility of attacking without the proper support. Shortly before six o’clock the sound of drums was heard on the reverse slope and Arthur muttered to Somerset, ‘This is what I feared. Come, we must act at once!’ He galloped over to the brigades commanded by General Maitland and General Pack and pointed towards the right of the line, the ridge above Hougoumont.

‘I need your fellows there at once. They are to form line.’

‘Line, your grace?’ Maitland looked anxious. ‘With cavalry present?’

‘It’s not cavalry that is the danger now. Lead your men forward directly.’

The two brigades doubled across the slope as the gun crews hurried back to their weapons and reloaded with canister. From the crest of the ridge Arthur was not surprised to see that the enemy cavalry had pulled back to allow their infantry to advance. They came on as before, in dense formations that quickly fell prey to the allied guns raking the slope with canister, and those that approached the ridge were suddenly caught in the flank by the volleys of the two brigades that had been ordered forward. Leaving hundreds of their comrades strewn amid the bodies of horses and riders left from the cavalry attacks, the rest fell back towards the French lines.

Arthur took stock of the situation. His squares, though unbroken, had suffered heavy casualties from the enemy’s artillery. The battalions of his Dutch allies were badly shaken and their officers and sergeants now stood to the rear ready to pounce on any man who fell out of line and thrust him back into position. Already one of his cavalry units, the Cumberland hussars, composed of inexperienced gentlemen, had turned away and was disappearing in the direction of Brussels.