The number of men that Edward II summoned to serve in 1314 and the scale of the preparations he put in train for his overdue expedition against the Scots suggest that this was a full-scale invasion aimed at nothing short of the total subjugation of the Scots. The compact between Philip Moubray and Edward Bruce merely added an urgency to the invasion preparations and introduced a deadline for Edward’s appearance before Stirling Castle. The immensely strong castle, perched on its rock dominating the town and the bridge over the River Forth, had been in English hands since Edward I took it in 1304. Any invasion of Scotland had to take account of its strategic position in the waist of Scotland at the first bridging point of the River Forth, guarding the narrow neck of land between the Firths of Forth and Clyde; its possession was the key to the north of Scotland.
The logistical planning of the campaign was left to capable officers, and the English army was well supplied by the commissariat on their well-ordered march north. King Edward had good intelligence reports of the preparations of the Scots before Stirling, he was not short of experienced advisors and appears to have been aware of the value of infantry in the difficult terrain in Scotland. Yet there is no evidence from events to show that Edward had any battle plan at all in mind at Bannockburn, nor did he display a control of his army that might have enabled him to have put a plan in motion. If the King had ever learned the lessons of the Welsh Wars and the battle of Falkirk, they were forgotten; there was no thought of combining infantry and cavalry in a planned attack. The headstrong knights were allowed to assert their independence by artlessly attempting to bludgeon their way through the ranks of the Scots. Edward’s assumption that the Scots would simply melt away before him was proved wrong by their aggressive resistance, and by the end of the first day’s fighting whatever plans the hapless King may have had lay in ruin. He lost control of events and the initiative passed to the Scots.
Robert Bruce knew that Edward II’s army could be expected before Stirling Castle by Midsummer Day of 1314. Bruce’s small, well-tried army became the nucleus of the larger army that he gathered in the Torwood in response to this threat. It is not certain that Bruce intended to fight a battle, though he clearly meant to harass the enemy in the woods through which the road to Stirling from the south ran, and may well have dug a series of ‘pottes’ or traps to impede the advance of the English cavalry. He was above all a cautious commander and throughout his career he displayed a reluctance to risk all on the uncertain outcome of a battle when the odds were against him, and he knew from his reconnaissance force that the English were advancing in great strength. During Edward II’s previous invasion of Scotland in 1310, Bruce’s response had been to withdraw into the interior leaving the land burnt and bare of food and forage until winter’s cold and rain and the escalating cost of supplying and paying a large army in the field forced the English to withdraw. Bruce’s dispositions in the New Park suggest that he had this course of action in mind. Defeat outside Stirling would have been ruinous for his cause and he must have pondered on the fate of Wallace and the plight of Scotland after the defeat at Falkirk.
But there were disadvantages in a Fabian strategy. Stirling would be relieved and the door to the north and the vital port of Perth would be open. Edward might gain far more than a toehold on the country before the onset of winter. It was high summer and the ranks of the Scots army were swollen with fresh fighting men eager for battle, so Bruce took care that his dispositions allowed him not only to withdraw safely but also to face about and fight if a favourable opportunity presented itself.