File:Photograph of Cecil & Rachel De Salis and their grandson Jerome, 1929.jpg

Summary
see 1988 Copyright, Designs and Patents Act : For literary, dramatic, musical or artistic works 70 years from the end of the calendar year in which the last remaining author of the work dies.
 * Other information:

If the author is unknown, copyright will last for 70 years from end of the calendar year in which the work was created, although if it is made available to the public during that time, (by publication, authorised performance, broadcast, exhibition, etc.), then the duration will be 70 years from the end of the year that the work was first made available.