Sir John on his willingness to co-operate), at a time when he sacked three of his own army commanders (including Lanrezac), ten corps commanders, and thirty-eight divisional commanders—Neillands writes that "one cannot help wonder" whether French would not have suffered the same fate had he reported directly to Joffre. Joffre believed at the time that the BEF were technically under his orders and that French's uncooperativeness was because the British government were too weak to insist that he obey orders. French was conscious that he was Joffre's senior in rank and had more combat experience. Marne and Aisne The BEF advanced to take part in the First Battle of the Marne on the morning of 6 September, Sir John's mood marred by a telegram from Kitchener urging him to co-operate with Joffre. This was the result of Joffre's appeal to Millerand, and Joffre repaired the damage by praising the performance of French and the BEF to Kitchener. The BEF began its advance from 20 km behind where Joffre had wanted it. Franchet d'Esperey, to the right of the BEF, was repeatedly demanding a quicker advance, and at 3.30 pm Sir John ordered Haig (I Corps, on the BEF right) to resume his advance, but by nightfall Haig was still 12 km away from his objective, having lost only 7 men killed and 44 wounded. The BEF advanced further on 7 September. Lord Ernest Hamilton recorded that "in the strict sense there was no battle ... the fighting ... was desultory". Charteris, Haig's intelligence adviser, thought the advance "absurdly slow" and noted that the cavalry moved behind the infantry. When the BEF reached the Petit Morin on 8 September, Marwitz's German cavalry broke off and retreated further, only for the BEF to halt because of a heavy thunderstorm. Joffre urged that it was "essential" that the BEF advance further. By 8 September, despite outnumbering the enemy by 10:1, the BEF had advanced just 40 km in three days. On 9 September Sir John, arriving on the spot in person, ordered I Corps to halt as soon as they had reached the main road, a mere 5 miles from the river (at midday Haig, who had halted for four hours after crossing the river after seeing aerial reconnaissance of German forces opposite him, probably Ilsemann's 5th German Cavalry Division, not IX Corps baggage train as he believed, had just given orders to