24Term of copyright in posthumous work.

(1) In the case of a literary, dramatic or musical work or an engraving, in which copyright subsists at the date of the death of the author or, in the case of any such work of joint authorship, at or immediately before the date of the death of the author who dies last, but which, or any adaptation of which, has not been published before that date, copyright shall subsist until ¹[sixty years] from the beginning of the calendar year next following the year in which the work is first published or, where an adaptation of the work is published in any earlier year, from the beginning of the calendar year next following that year.
(2) For the purposes of this section a literary, dramatic or musical work or an adaptation of any such work shall be deemed to have been published, if it has been performed in public or if any ²[sound recordings] made in respect of the work have been sold to the public or have been offered for sale to the public.