The cherry picked list of orders to burn and destroy are not representative of his entire demeanour towards civilian populations, which was commented on readily by most observers during his lifetime.... Overall when seen within the proper context, the view presented within the quotation marks proves (to those that know) little but that commanding officers are forced to act ruthlessly in the pursuance of their duty. It is regrettable that the list has already been swallowed by some and carried away to portray Wellington as a monster.

Here is the entire passage from which the Garrard Glenn reference quoted earlier is taken ('The Army and the Law' (1918):

When Wellington, with an auxiliary Spanish army moving with him, crossed the Bidassoa in 1813, and stood upon the invaded soil of France, he had to meet two difficulties ; the Spanish army took to plundering, and this excited the French peasantry to acts of hostility. Wellington was equally firm on both points. The Spanish commanders he admonished that plundering must cease, or their forces could no longer march with him.

He had not lost thousands of men to enable the Spaniards to pillage and ill-treat the French peasantry ; he preferred a small army obedient to a large army disobedient and undisciplined. The question between them was whether they should or should not pillage the French peasants. His measures were taken to prevent it, etc.: On the other hand, when the Spanish plundering had made the peasants rise in arms, Wellington issued a proclamation requiring them either to join Soult's army or stay at home, otherwise he would bum villages and hang the inhabitants." pp74-75

(See Wellington's summation of martial law: "Martial law is the will of the commanding officer of an armed force or of a geographical military department, expressed in time of war, within the limits of his military jurisdiction, as necessity demands and prudence dictates...")