The author has declared that this work created by the United Kingdom Government is in the public domain.
This is because it is one of the following:
- It is a photograph taken prior to 1 June 1957; or
- It was published prior to 1974; or
- It is an artistic work other than a photograph or engraving (e.g. a painting) which was created prior to 1974.
You may wish to see this on crown copyrights for more information.