On the front of the main allied group the "annihilation plan" was crippled at the outset by the tardiness of the archduke's (fifth or left) column. On this the smooth working of the whole scheme depended, for Coburg considered that he must _defeat_ Bonnaud before carrying out his intended envelopment of the Menin-Courtrai group (the idea of "binding" the enemy by a detachment while the main scheme proceeded had not yet arisen). The allied general, indeed, on discovering the backwardness of the archduke, went so far as to order all the other columns to begin by swerving southward against Bonnaud, but these were already too deeply committed to the original plan to execute any new variation. The rightmost column (Hanoverians) under von dem Bussche moved on Mouscron, overpowering the fragmentary, if energetic, resistance of the French advanced posts. Next on the left, Lieutenant Field Marshal Otto moved by Leers and Watrelos, driving away a French post at Lis (near Lannoy) on his left flank, and entered Tourcoing. But meantime a French brigade had driven von dem Bussche away from Mouscron, so that Otto felt compelled to keep troops at Leers and Watrelos to protect his rear, which seriously weakened his hold on Tourcoing. The third column, led by the duke of York, advanced from Templeuve on Lannoy, at the same time securing its left by expelling the French from Willems. Lannoy was stormed by the British Guards under Sir R. Abercromby with such vigour that the cavalry which had been sent round the village to cut off the French retreat had no time to get into position. Beyond Lannoy, the French resistance, still disjointed, became more obstinate as the ground favoured it more, and the duke called up the Austrians from Willems to turn the right of the French position at Roubaix by way of a small valley. Once again, however, the Guards dislodged the enemy before the turning movement had taken effect. A third French position now appeared, at Mouvaux, and this seemed so formidable that the duke halted to rest his now weary men. The emperor himself, however, ordered the advance to be resumed, and Mouvaux too was carried by Abercromby. It was now nightfall, and the duke having attained his objective point prepared to hold it against a counter attack. Kinsky meanwhile with the fourth column had made feints opposite Pont-a-Tressin, and had forced the passage of the Marque near Bouvines with his main body. But Bonnaud gave ground so slowly that up to 4 P.M. Kinsky had only progressed a few hundred paces from his crossing point. The fifth column, which was behind time on the 16th, did not arrive at Orchies till dawn on the 17th, and had to halt there for rest and food. Thence, moving across country in fighting formation, the archduke made his way to Pont-a-Marque. But he was unable to do more, before calling a halt, than deploy his troops on the other side of the stream.