‘Good news indeed.’ He turned to Somerset. ‘It seems that our eastern allies crossed the Rhine three days before Christmas. They have begun the invasion of France. Bonaparte has too few men to do anything but mount a fighting withdrawal.’ Arthur lowered the letter. ‘The time to act is upon us, and our allies urge us to renew our offensive. However, we cannot advance while the weather and the ground are against us. In the meantime, then, we must prepare the army to break camp and march against the French. No later than the middle of February.’

‘What about the roads, sir? What if they are still impassable?’

Arthur considered the possibility for a moment. ‘When the finishing line is in sight, then damn the mud! We shall have to advance in any case.’

The following month Hill’s corps left their winter quarters and advanced to screen the activities of the rest of the army. At the same time a flotilla of hired boats and small ships made their way up the coast from St-Jean-de-Luz to the mouth of the Adour. The weather had moderated, clearing the sky and adding to Arthur’s good humour now that the campaign was under way again. Under the cover of the guns of a frigate and a battery of cannon on the south bank of the Adour, the engineers began to anchor the craft side by side in the estuary and lay down a wooden road across their decks. The far bank was lightly defended, and the enemy fell back the moment the first roundshot came their way.

Towards the end of the first day the bridge was nearly complete and a Portuguese brigade had been landed on the far shore, together with a handful of guns and a rocket battery. Arthur had crossed the river to oversee the establishment of the bridgehead when there was an exchange of musket fire from the road to Bayonne. A moment later a soldier came trotting back to warn that an enemy column was approaching. Colonel Wilson, the commander of the brigade, immediately formed his men up across the road ready to defend the small party of engineers constructing the landing stage on the north bank. The guns and the rockets were in place on a small mound overlooking the river and Arthur gestured to Somerset to follow him and rode up to the two batteries for a better view.

To the east the road snaked between undulating ground, and Arthur could see tiny puffs of smoke as the Portuguese skirmishers exchanged fire with the light infantry advancing in a line in front of the main French column.

‘A division, I should say.’

‘And cavalry, there, towards the rear, sir,’ Somerset said quietly.‘Could cause us some difficulty.’