This plan had to be wholly recast. The British and French Governments decided that Haig must take over a longer front, and before the end of February 1917 the British right was as far south as a point opposite the town of Roye. Again, the retreat of the Germans during February and March 1917 destroyed the salient which Haig had purposed to attack. There now remained nothing of the preliminary movement as originally planned, except the carrying of the Vimy Ridge. But a fresh scheme had been proposed by the French and accepted by the British Government. Under the new French Commander-in-Chief, Nivelle, an ambitious operation was conceived on the heights of the Aisne, which, it was trusted, would open the way to Laon. In this action the old method of limited objectives was to be relinquished; and Nivelle hoped, by means of his new tactics and by an unexampled concentration of troops, to break through the enemy lines on a broad front and restore the war of movement. This attack was fixed for the middle of April. It would operate against the southern pivot of the Siegfried zone, and it was arranged that Haig should use his forces against the northern pillar east of Arras, and should strike a week before. The position was, therefore, that the Arras battle, which Haig had regarded as only a preparation for the main campaign of the season in Flanders, became the principal task of the British Army during the first half of 1917. This battle in turn was conceived as an action subsidiary to the greater effort of the French in the south. It was admittedly an attack in a region where, except for an unexampled piece of fortune, great strategic results could scarcely be obtained. The British success depended upon what the French could do on the Aisne. If Nivelle failed, then they, too, must fail in the larger strategic sense, however valuable might be certain of their local gains. If, however, Nivelle succeeded, the pressure from Arras in the north would beyond doubt greatly contribute to the enemy’s discomfiture. The danger of the whole plan was that the issue might be indeterminate and the fighting at Arras so long protracted, without any decisive success, that the chances of the more vital Flanders offensive later in the summer would be imperilled. This, as we shall see, was precisely what happened. [Sidenote: _Jan. 14, 1917._]