All being prepared for a move, the British army commenced their advance from Salamanca on December 11th, with intention of marching direct to Valladolid; but on the arrival at headquarters at Alaejos, on the 13th, an intercepted despatch from the Prince of Neufchâtel to the Duke of Dalmatia was brought to the general. These despatches were of such a nature as to induce our general to deviate somewhat from the route intended. Leaving Valladolid more to our right, our headquarters were removed to Toro.
On the night of the 14th General Charles Stuart, with a detachment of the 18th Dragoons, surprised a detachment of the enemy, consisting of fifty infantry and thirty cavalry, cutting down or taking prisoners almost all of them. One dragoon who escaped carried the report of the destruction of the detachment, and was scarcely credited by General Franceschi, who commanded about four hundred cavalry at Valladolid; for previous to this surprise the French were fortunately in total ignorance of our vicinity, reasonably concluding that by all the rules of war we were in full retreat towards Portugal.
The reserve, in the meantime, arrived at Toro, where the advanced guard of General Baird’s corps, consisting of the cavalry under the command of Lord Paget, joined Sir John Moore’s army.
It now being evident that after the surprise of their outpost at Rueda the enemy could no longer be ignorant of our advanced movements, Sir John Moore pushed on his columns as fast as the severity of the weather would permit. On the 16th the reserve were at Puebla, on the 17th at Villapando. On the 18th headquarters were at Castro Nuevo. On the 19th the reserve continued their march, and on the 20th reached Santarbas. On this day the whole of the army were united, and so far concentrated as shelter and deep snow would permit. The weather was excessively severe, and the flat bleak country could furnish but little fuel.
Lord Paget, being informed that General Debelle, with from six to seven hundred dragoons, was in the town of Sahagun, marched on the night of the 20th, with the 10th and 15th Hussars, from the different small villages where they were posted in front of the army at Mayorga. The 10th marched directly for the town, and the 15th led by Lord Paget endeavoured to turn it by the right and thus cut off the enemy’s retreat; but his advance was unfortunately discovered by a patrol, and the French had time to form on the outside of the town before the 15th could get round. When therefore his lordship arrived at the rear of the town about daybreak, with four hundred of the 15th (the 10th not being as yet come up), he discovered a line of six hundred cavalry in a field close to the town and prepared to oppose him. They were drawn up in rear of a ravine which protected their front from being charged. But in those days the superior numbers or strength of position of the French cavalry had very little influence over our dragoons. After manœuvring a very short time, each party endeavouring to gain the flank of their opponent, Lord Paget charged with his wonted vigour, broke the enemy’s line, and chased them off the field. The result of this gallant affair was a loss on the enemy’s side of twenty men killed, two lieutenant-colonels, eleven other officers, and one hundred and fifty troopers prisoners; while the loss on our side amounted only to six men killed and from fifteen to twenty wounded.