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. [Sidenote: COMBAT OF CAVALRY.]