This was a very necessary move for the following reason: when—if ever—the tunnel was used in earnest, it would be used after dark and lock-up. Consequently those who intended to use it would have all to be in B Kaserne at the time. For any less important occasion it might have been feasible for the A house members of the scheme to arrange to change places for the night with accomplices in B house, the A house officers answering to the B house officers’ names and _vice versâ_. This used to be done sometimes for occasions such as a birthday party or a theatrical show, when the presence of some member of the other house was essential to the success of the evening’s programme. But more often than not it was spotted, and either condoned or reported according to the nature and temper of the Feldwebel taking the _appel_. On a large scale and for an event of the nature of the tunnel, for the success of which complete absence of any suspicion on the part of the Germans was an absolute _sine qua non_, such a risk was not possible, and, indeed, could not be allowed. It was intended that, whatever happened, and whatever the hardship that might occur in individual cases, the night of the escape should not find a single officer in B Kaserne who was not domiciled there with the permission of the Germans. This intention was happily carried into effect. Meanwhile, the owners of the founders’ shares, knowing, as they did, pretty well the conditions under which the scheme was to be submitted to the public, took time by the forelock and changed houses before the rush. It was indeed an undertaking in which the home policy was fraught with almost as many dangers as the foreign, and required the most patient and tactful handling. Fortunately there was only one of the allied nations in the camp, and this fact of itself quartered the risk. Inter-allied jealousy, or merely Latin or Slavonic exuberance, had many a time ere this during the war wrecked a promising and well-laid plan. But even in a camp where all were English and the loyalty to the cause of the whole community never for an instant came in question, there were yet grave risks of discovery through some intemperate speech or action of the newly captured or the not overwise.