File:Carson signing Solemn League and Covenant.jpg

Licensing
Reasoning for new PD-UK licence:

Newly found sources clearly indicate date of creation and there is no evidence of author, so a 70-year term in the UK is appropriate. If it was an official photo covered by crown copyright the image would have come into the public domain after 50 years.

Old justification for retaining on English Wikipedia:

PD in the US since it was published before 1923. However, no source exists for this image, so until this is fixed, its copyright status cannot be determined in its country of origin (Great Britain). This makes this image incompatible with Commons' rules.