Franco-British Staff Meetings at Rabat, May, 1939. Commentary by the Joint Intelligence Sub-Committee

interception particularly if French ciphers, which are believed to be less secure than our own, are used. They therefore recommend that the local authorities in North Africa should be asked to bear in mind the dangers of interception and should be requested to arrange that no important messages should be sent by wireless or by cable liable to interference. 4. In order that a secure means of sending important messages by the quickest route may be available it is felt that there is a definite need for a suitable code for inter-allied use in peace time.