Warning: The Sharp Ears of Enemy Agents Are Always Listening for Scraps of Information

A text-only poster under the Canadian coat of arms lists seven subjects not to discuss, from ship movements to supply stores. The tells are the unseen 'Enemy Agents' always listening, which makes ordinary talk a danger, and the coat of arms, which lends state authority.

Propaganda techniques used in this poster

Fear appealTransfer

Date

1940

Period

Second World War

Made by

Director of Public Information, Ottawa, by authority of Hon. James G. Gardiner, Minister of National War Services

Region

North America

Country

Canada

Medium

Poster

Issuer type

State

Regime

Mackenzie King Government

Leader

William Lyon Mackenzie King

Audience

Domestic public

Purpose

Warn or inform

Themes

Security and surveillance, War and the military, Home front

Event

World War II

Source

Identified Openly sourced: the speaker is who they say they are

Source

U.S. National Archives and Records Administration, Record Group 44, World War II Foreign Posters, retrieved October 3, 2026

Rights

Public domain (Canadian Crown copyright, 50 years from publication, expired; no URAA restoration)
Director of Public Information, Department of National War Services (Canada), c. 1940. U.S. National Archives, Record Group 44.

WARNING

The sharp ears of Enemy Agents
are always listening
for scraps of information

DON'T LET YOUR CARELESS
TALK HELP THE ENEMY

DO NOT DISCUSS
SHIP MOVEMENTS
DEFENCE PLANS
MUNITIONS FACTORIES
TROOP MOVEMENTS
HARBOUR FACILITIES
AIRCRAFT PRODUCTION
SUPPLY STORES

BE ON YOUR GUARD

Issued by the Director of Public Information, Ottawa, by Authority
of Hon. James G. Gardiner, Minister of National War Services.

[motto on the arms:] A MARI VSQVE AD MARE