which they did within an hour of take-off. At the suggestion of Major Trenchard (who was accompanying one of the pilots), the Blue aircraft were then dispatched to inform the Blue cavalry of the enemy location. The intervention of aircraft handed Grierson the element of surprise and, although the Red forces also employed aircraft, they were unable to regain the initiative. According to his diary, Grierson "stayed in camp all day receiving reports and very soon locating all the lines of march and halting places of the Red forces". 17 September 1912 Blue cavalry advanced to locate the enemy and fought with the 2nd Division near Hundon in Suffolk. The 3rd Division ended the day in position from Reid's Farm to Rivey Hill. The 4th Division concealed itself from aircraft and, after dark, moved through Saffron Walden and camped to the east of it. 18 September 1912 The Blue infantry was ordered to advance to the line Horseheath—Helions Bumpstead. The hitherto concealed 4th Division closed up on the right of the 3rd, which had been strung out to represent the main force. The Blue cavalry was ordered to co-operate on the right of the 4th Division and the Territorials to advance from Cambridge to Linton. In the ensuing 'battle', Blue forces won a clear victory, bringing the manoeuvres to a close a day early. Grierson had the 10th Brigade in hand. Although the Red cavalry were somewhere to the rear of the Blue forces, they were not deployed in the battle. Haig was thus defeated in front of his own staff, the King, and the foreign observers. The Blue forces bivouacked at Linton and Grierson celebrated his victory with champagne. 19 September 1912 At the final conference in Trinity Hall, the King presiding, the opponents were asked to explain their tactics and moves. Grierson was well received. "He looked like victory", said one observer. His speech was confident, lucid, and vigorous. In contrast, Haig's speech was disastrous. According to John Charteris, he did not read out his written statement, which gave a "clear and convincing account of his views, he did not even refer to it when he spoke but to the dismay of his staff attempted to extemporise. In the effort he became totally unintelligible and unbearably dull. The university dignitaries soon fell asleep, Haig's friends became more and more uncomfortable, only he seemed totally unconscious of his failure."