German Spies in England by William Le Queux

We shall probably never be able to realise a hundredth part of what Germany has done by her spy system, but we know enough to realise that, for years, no country and no walks of life -- from the highest to the lowest -- have been free from the presence of her ubiquitous and unscrupulous secret agents. Nothing in the way of espionage has been too large, or too small, for attention.

Her spies have swarmed in all cities, and in every village; her agents have ranked among the leaders of social and commercial life, and among the sweepings and outcasts of great communities. The wealthiest of commercial men have not shrunk from acting as her secret agents. She has not been above employing beside them the very dregs of the community. No such a system has ever been seen in the world; I hope it is safe to say that no such system will ever be seen again. Indeed, so despicable is this German spy system that even the leader of the Opposition in the Reichstag, Herr Richter, one day rose from his seat and protested against "the more than doubtful morality of the individuals employed. " This protest was made because it was known that the Secret Service of Germany countenanced rank immorality and vice, the suborning of high officials, and the shameless engagement of women of ill-fame in the search for information.