Each night the sodden redcoats found what shelter they could and lit fires to warm their cold bodies and attempt to dry their clothes. Meanwhile Arthur read the reports of his scouts with a mixture of frustration and grudging satisfaction. Soult was marching at a faster pace than his own men could manage, but only at the price of steadily abandoning his guns and wagons. Soon all he would be left with would be his footsore infantry and the starving, lame mounts of his cavalry.

In an effort to prevent Soult’s escape Arthur despatched a Portuguese column to try to march round the enemy’s flank and block their passage across the hills into Spain. Another column, led by Beresford, blocked any escape to Vigo in the north where Soult might join forces with Ney. At last, the desperate French commander abandoned the roads and led his forces over the mountains of Santa Catalina. As soon as he heard the news Arthur realised the chase was up. It was five days since they had set out from Oporto, and without abandoning his own guns and supply train he could no longer pursue Soult with the main body of his army. Riding on with his cavalry, he followed Soult’s tracks across the mountains and on the seventh day of the pursuit, as the cavalry descended towards the broken country of Galicia, Arthur halted his column.

No more than five miles ahead he could see the remnants of Soult’s corps, moving like a band of beggars across the landscape.There was little sense of order in the straggling mass of humanity and only a handful of cavalry formations retained enough discipline to form a rearguard.

‘We have them, sir!’ Somerset said eagerly. ‘We have but to charge and they will scatter to the winds.’

Arthur stared after his enemy for a moment and then shook his head.

‘Sir?’

‘Do you not know where we stand, Somerset?’ Arthur gestured to the ground before them. ‘That is Spain. I am forbidden from entering without the express permission of the Secretary for War.’

‘But sir,’ Somerset protested, pointing at Soult’s ragged column.‘One charge and they will break.’