So called governors of Scotland were frequently appointed and as often superseded, but no effectual aid was given them to enable them to check the ever spreading insurrection. But Perth was now threatened by Bruce; and the danger of this, the strongest and most important northern fortress, roused Edward from his lethargy. A fleet was fitted out for the Tay. Troops, under the Earl of Ulster, were engaged to be transported by an English fleet of forty ships, supplied by the seaports, and intended to cooperate with John of Lorne in the west. Edward himself, with a powerful army, accompanied by the Lords Gloucester, Warrenne, Percy, Clifford, and others, advanced into Scotland as far as Renfrew. Bruce could oppose no effectual resistance in the field to so large a force, but he used the tactics which Wallace had adopted with such success. The country through which the English were advancing was wasted. Flocks and herds were driven off, and all stores of grain burned and destroyed. His adherents, each with their own retainers, hung upon the skirts of the English army, cutting off small parties, driving back bodies going out in search of provisions or forage, making sudden night attacks, and keeping the English in a state of constant watchfulness and alarm, but always retiring on the approach of any strong force, and avoiding every effort of the English to bring on an engagement.
The invaders were soon pressed by want of provisions, and horses died from lack of forage. The great army was therefore obliged to fall back to Berwick without having struck a single effective blow. After this Edward remained inactive at Berwick for eight months, save that he once again crossed the Border and advanced as far as Roxburgh, but only to retreat without having accomplished anything. The Earls of Gloucester and Warrenne reduced the forest of Selkirk and the district, and restored the English power there; while the king’s favourite, Piers Gaveston, Earl of Cornwall, went by sea to Perth and tried to reduce the surrounding country, but the Scotch, as usual, retired before him, and he, too, after a time, returned to Berwick. The efforts of the defenders to starve out the invading armies of England were greatly aided by the fact that at this time a great famine raged both in England and Scotland, and the people of both countries were reduced to a condition of want and suffering. Not only did the harvest fail, but disease swept away vast numbers of cattle and sheep, and in many places the people were forced to subsist upon the flesh of horses, dogs, and other animals.