The Prussian bowed his head again and turned to stride back towards the entrance of the house Arthur had rented in the heart of the city. Arthur turned to the staff officer. ‘Get to headquarters at once. Tell Somerset to issue orders to every formation. The army is to form up and be ready to march as soon as orders are issued.’

‘Yes, sir.’ The officer turned away and increased his pace.

‘Walk, my boy, don’t run! We must appear calm in front of the local people.’

‘Yes, sir,’ the young officer replied, chastened.

Arthur returned to the dining room and sat back down. Picking up his fork he rapped the side of his glass. ‘Quiet, gentlemen.’

The officers turned towards him.

‘The French have crossed the border,’ he announced. ‘They attacked one of Blücher’s formations.’

‘At last.’ Uxbridge smiled. ‘Where was this?’

‘At Thuin. The question is, does this constitute the main thrust of their attack, or is it a feint?’

‘A feint?’ Picton growled. ‘Are you saying that Boney’s trying to lure us towards the Prussians? That makes no military sense to me.’

‘It does, if he means to break through on our right and sever our communications.’ Arthur paused. ‘That is what I believe his intention to be, for the present. To guard against that possibility, the army will concentrate to the west of Thuin. If there is any indication that this is not a feint, then we will adjust our position accordingly. I have given the order for the army to make ready to march. I will also send an order to General Dörnberg at Mons to probe for any sign of the enemy to his front. Meanwhile we shall wait until the situation becomes clear. Now, gentlemen, you know my policy with regard to the local people and our own civilians. We will attend tonight’s ball and there is to be no mention of this attack. I suggest you make the most of the entertainment, since it may be the last such occasion for a while.’

Shortly after ten o’clock Arthur was talking to Uxbridge when he saw the guests stir by the entrance to the ballroom as a figure in a riding cloak entered and scanned the room. Arthur recognised him at once - General Müffling, the officer assigned to liaise between the headquarters of the two allied armies. As soon as he caught sight of Arthur the Prussian hurried through the crowd towards him.

‘I fear the game is up,’ Arthur muttered as the dancing stopped and the orchestra fell silent. All eyes were turning towards him.

‘So it seems.’ Uxbridge nodded.

Müffling had been riding hard and his cloak and boots were smeared with mud. ‘Sir, Marshal Blücher sent me.’

‘Come.’ Arthur placed an arm on the Prussian’s shoulder. ‘Let us converse somewhere quiet, and I shall have refreshments brought to you.’