lines, either in uniform or en civil, during the progress of an ac- tion; crossing the enemy lines and landing behind them in an aeroplane, either by the machine coming to the ground or by means of a parachute; crossing similarly in a free balloon; or crossing a frontier guarded by sentries and electrified wire, by evading or killing the sentries, and climbing the wire in insulated boots and gloves. False papers, disguises, secret ink and all the other tricks beloved of the spy novel may form part of their equipment, but normally the less theatrical the spy the less likely he is to attract attention. In practice, the most dangerous and efficient spy is probably the least sensational in his methods; when arrested he invariably has all his papers in order and is the most plausible person alive. Men, women and even chil- dren of all grades of society and of all professions, may render services of varying degrees of importance, but all useful to a system of espionage. A spy system in war involves the employ- ment of many thousands of persons: post-boxes, passeurs, con- trebandistes and guides, train watchers, pigeon men, couriers, runners, reliables who will give shelter to agents and escaped prisoners, and notables who are capable of organizing a service. All have their respective parts to play behind the lines in modern war; and that part, far from being ignoble, may be, if actuated by patriotism, as noble, as dangerous and as heroic as any played in the armies in the field.
In spite of all the precautions adopted as the result of expe- rience in the World War, the collecting of information is not the difficulty; that lies in the transmission of information when obtained. Over this subject a veil, unfortunately, must be drawn. Agents may carry pigeons to send back, or portable wireless sets for communication with their employers, and messages have been shot over a neutral frontier by crossbow. The use of directional wireless and ordinary vigilance and common sense soon lead, however, to discovery, and necessitate a change of venue for the agent, and the application of fresh methods after a short time. It is only necessary here to say that, contrary to a popular belief, signalling by an agent by any means from, or close behind, the enemy lines is almost impossi- ble, except in open warfare. In trench warfare, even if it were possible, it would be of little use, as any information to be gained there is better obtained by other means. The agent's useful information is gleaned much farther back, and to get it he requires a thorough and careful training. Apart from the control of agents and of the administrative, financial and clerical questions involved in that work, the duties of the chief of this sub-section are to get information by all possible means. Amongst other methods employed in the late war was the drop- ping of pigeons by automatic release from free balloons. Advan- tage was taken of the wind's force and direction to regulate their fall in or near any desired neighbourhood, and there they were picked up by the inhabitants. Following the instructions enclosed, the latter often gave rapid and valuable information as to the movements of the enemy.
Another form of activity on which agents may be advan- tageously employed is sabotage, i.e. the destruction in the field of bridges, telegraphs, lock gates- and communications, and of munition factories and similar organizations in enemy home territory. The Germans are alleged to have employed these methods, even in neutral countries, where munitions and war material were being manufactured for the Allies. In the field, such work is most advantageously linked up with operations, either just before they begin or whilst they are in progress. If contemplated as a prelude to operations it must always be re- membered that they may serve as warning of an offensive. In any event the officer directing such schemes must remember the probable consequences to an allied population in territory occupied by the enemy, on whom punishment will be visited. Sabotage of this sort is naturally easiest in crowded centres, where circulation is difficult to control; and although in war risk to human life, even of non-combatants, must in some cases be a secondary consideration, this fact alone requires that sabotage, if undertaken, should be expected to have definite results.
The duties of the other, the defensive, sub-section are popular-
ly described as contre-espionnage. Although the duties, as in the case of Secret Service so called, are the same in peace as in war, the machinery and methods vary considerably according to the conditions under which they are carried out. The vary- ing conditions referred to are: (i) in home territory, in peace and in war; (2) in allied territory; and (3) in enemy or occupied territory. In the two latter cases war conditions only come into consideration.
Of these varying conditions the first provides, perhaps, the easiest problem. The contre-espionnage section commands, in peace and in war, all the assistance of trained police through- out home territory; of censorship; of port control; of hotel registration; of the erection of arbitrary barriers such as pro- hibited areas; and of all the preventive measures which may be the outcome of years of experience in combating enemy espio- nage under all conditions. Although Intelligence (B) in the ( field in occupied territory would equally enjoy these powers, and, in addition, the arbitrary powers of the conqueror in the territory of the conquered, and would have the advantage of knowing that the whole population is potentially hostile, the machinery at its disposal to cope with it would be largely improvised and, therefore, at first, not so efficient. In allied territory the difficul- ties are greater, as it is the ally who, naturally, controls in his own home territory all the real preventive machinery. He is, in addition, possibly susceptible about interference with either his C.E. Organization, or with the native population. Under these conditions contre-espionnage is carried on largely on sufferance, and requires the exercise of much discretion and tact.
It is necessary to remember that the object of contre-espion- nage is, first and foremost, prevention. The catching of spies, interesting though it is, is entirely subsidiary; its principal value lies in disclosing the holes in the preventive net and in directing the attention of the controlling staff towards the proper remedies to be applied. In the zone of the armies the principal value of an efficient conlre-espionnage system is a moral one. Troops and their commanders must be relieved of their anxieties about enemy activities in their midst; but from what has been written above it will be seen that those anxieties are often based on not very solid grounds, at least in trench warfare. Troops com- monly attribute to an enemy secret service of any efficiency powers far beyond the capacity of any S.S. Organization. It is, of course, the effect of the unknown on mass psychology; but the influence on moral may be prodigious unless means are taken to check it.
From what has been stated it will be seen that the contre- espionnage sub-section falls naturally into two divisions: (i.) the investigation of suspected cases of espionage, and (ii.) the control of the population. It is not possible to enlarge on the methods of investigation employed by a contre-espionnage serv- ice; although in general they resemble ordinary police detective methods, in details they differ widely from them. They require technical knowledge not usually possessed by ordinary police personnel; and even trained police-detective staffs require special training to be useful in contre-espionnage.
In endeavouring to prevent the collection of information by the enemy's agents it is necessary to remember that this may be gained equally (i.) from your own troops and (ii.) from the civil population. The former may sell or convey information delib- erately, but it is far more probable that they may convey it to the enemy's agents through their indiscretions. Investigation of treachery requires no difference in treatment, whether it occurs among troops or civilians, and the question need not therefore be further examined. The problem of dealing with leakage of information through indiscretion, however, is a differ- ent one, and requires special consideration. " Leakage " may occur in several ways; gossip amongst the troops about impend- ing operations, especially when they are on leave and out of the line; indiscreet conversations and messages on field telephone and buzzer; misuse of code in telegraph and wireless; marking of railway trucks, transport and billets, with inscriptions which give identifications of units; indiscretion in correspondence; careless handling of confidential papers and books; taking
