It has long been nagging me about the policy of HMSO with respect to
Crown copyright material outside of the UK. Inside the UK the position
is clear: published material from 1954 or earlier is out of copyright
as it was published over 50 years ago. Outside the UK the position of
Crown copyright material has long been ambiguous.
I therefore sent a Freedom of Information Act request to the Office
for Public Sector Information (what HMSO has changed its name to)
requesting clarification of the length of copyright for published
Crown copyright material outside the UK. I received the following
reply from their Information Policy Adviser:
Thank you for your email enquiry dated May 23rd, 2005. Crown
copyright protection in published material lasts for fifty years from
the end of the year in which the material was first published.
Therefore, to use your example, material published in 1954, and any
Crown copyright material published before that date, would now be out
of copyright, and may be freely reproduced throughout the world.
I hope this information will be helpful to you, but if you have any
further questions please feel free to get in touch with me again."
So, it appears that Crown copyright material that has been published
in 1954 or earlier is considered public domain worldwide by OPSI and
is thus fair game for the Wikipedia to use.