These are in copyright until the end of 70 calendar years following the death of the photographer, if known. Copyright will remain with the legally appointed heirs of the photographer unless the right is ceded to a 3rd party. If the photographer's identity is not known, copyright will expire at the end of 70 calendar years following the date that the photograph was taken. For example, copyright in a photograph taken on 7 July 1941 will expire on 1 January 2012 if the photographer is not identified, or later at the end of 70 calendar years following his/her death if their identity is known.
There are also instances where a photograph can be deemed to have been commissioned by an institution or company. An example would be images of wagons appearing in the photograph albums of the Gloucester Railway Carriage & Wagon Company. In this case, the Company as the commissioning body would be deemed to be the owners of intellectual property rights in the images, rather than the photographer who actually took the shots. In this instance images will remain in copyright for 70 years after the demise of the Company, and would be owned by the successor firm, unless this right has been ceded to the Archives.