December 1941 Notice concerning <a href="https://en.wikipedia.org/wiki/Postal_censorship" class="extiw" title="w:Postal censorship">postal censorship</a> between Great Britain, Northern Ireland and Éire during World War II issued by <a href="https://en.wikipedia.org/wiki/Postmaster_General_of_the_United_Kingdom" class="extiw" title="w:Postmaster General of the United Kingdom">Postmaster General</a> and <a href="https://en.wikipedia.org/wiki/Ministry_of_Information_(United_Kingdom)" class="extiw" title="w:Ministry of Information (United Kingdom)">Ministry of Information</a>
<a href="https://en.wikipedia.org/wiki/General_Post_Office" class="extiw" title="w:General Post Office">General Post Office</a>
scan from own collection