These are the limits :
Duration of copyright
The 1988 Copyright, Designs and Patents Act states the duration of copyright as;
1. 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.
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.), copyright will run for 70 years from the end of the year that the work was first made available.
2. Sound Recordings and broadcasts
50 years from the end of the calendar year in which the work was created, or,
if the work is released within that time: 50 years from the end of the calendar year in which the work was first released.
3. Films
70 years from the end of the calendar year in which the last principal director, author or composer dies.
If the work is of unknown authorship: 70 years from end of the calendar year of creation, or if made available to the public in that time, 70 years from the end of the year the film was first made available.
4. Typographical arrangement of published editions
25 years from the end of the calendar year in which the work was first published.
5. Broadcasts and cable programmes
50 years from the end of the calendar year in which the broadcast was made.
I acutally looked for it.