Aaron Rodd Diviner by E. Phillips Oppenheim

Cresswell and Aaron Rodd were dining with Captain Brinnen and his sister at a corner table in the Milan Restaurant. Harvey Grimm had once more left them for an unknown destination, and they were all aware that the period of his absence would be this time more than ever one of strain. As though by general consent, however, the conversation did not touch once upon personal matters. They spoke a good deal of the war. Brinnen himself was roused by sundry reflections into a momentary bitterness, an expression of that peculiar irritation common to many of his country-people, notwithstanding their underlying gratitude.

"You people in England," he declared, "you have no perceptions, no brains with which to combat a perfectly-developed system of espionage; nothing but an infinite complacency, an infinite stupidity. The people who hate you walk in your midst, unharmed. Even if they are pointed out, your officials shrug their shoulders and smile in a superior fashion. 'They can do us no harm,' they assure you. 'There are reasons why we prefer to leave them alone. ' And you are at war, you people! Ah, if only you would realise it!"