German Spies in England by William Le Queux

We know, from official sources, that in spite of all the foolish self-congratulation of Mr. McKenna and his friends -- who are "getting on" towards Birthday Honours, -- and his attempt to gag the _Globe_, there are some 27,000 alien enemies still at large in Great Britain, and upon their activities on their country's behalf, until recently our only check was the shadowy form of "registration" that we have adopted. Even many of those interned are now being released upon bonds being given by responsible citizens.

Unfortunately, anyone who ventures to suggest that these people -- whose bonds may be signed by persons in German pay -- may constitute a very serious danger, is at once branded, officially, as an alarmist, and accused of attempting to manufacture a "spy scare," whatever official optimists may mean by that term.