Eventually I decided that, despite the various limiting factors, I could muster enough force to make a first success sufficiently sure to justify undertaking the attack, but that the degree to which this success could be followed up must depend on circumstances. It was calculated that, provided secrecy could be maintained to the last moment, no large hostile reinforcements were likely to reach the scene of action for forty-eight hours after the commencement of the attack. I informed General the Hon. Sir Julian Byng, K. C. B., K. C. M. G., M. V. O., to whom the execution of the plans in connection with the Cambrai operations was intrusted, that the advance would be stopped by me after that time, or sooner if necessary, unless the results then gained and the general situation justified its continuance. Plan of Attack The general plan of attack was to dispense with previous artillery preparation, and to depend instead on tanks to smash through the enemy's wire, of which there was a great quantity protecting his trenches. As soon as the advance of the tanks and infantry, working in close co-operation, began, the artillery was to assist with counter battery and barrage work; but no previous registration of guns for this purpose could be permitted, as it would rouse the enemy's suspicions. The artillery of our new armies was therefore necessarily subjected to a severe test in this operation, and proved itself entirely worthy of the confidence placed in it. The infantry, tanks, and artillery thus working in combination were to endeavor to break through all the enemy's lines of defense on the first day. If this were successfully accomplished and the situation developed favorably, cavalry were then to be passed through to raid the enemy's communications, disorganize his system of command, damage his railways, and interfere as much as possible with the arrival of his reinforcements. It was explained to all commanders that everything depended on secrecy up to the moment of starting, and after that on bold, determined, and rapid action. Unless opposition could be beaten down quickly, no great results could be looked for.