(1) Copyright in a literary, dramatic, musical, or artistic work is not infringed by any act done at a time when, or in pursuance of arrangements made at a time when,—
(a) it is not possible for a person who wishes to do so to ascertain the identity of the author by reasonable inquiry; and
(b) it is reasonable to assume—
(i) that copyright has expired; or
(ii) that the author died 50 years or more before the beginning of the calendar year in which the act is done or the arrangements are made.
(2) Subsection (1)(b)(ii) does not apply in relation to—
(a) a work in which Crown copyright exists under section 26; or
(b) a work—
(i) in which copyright originally vested in an international organisation under section 28; and
(ii) in respect of which an order made under that section specifies a copyright period longer than 50 years.
(3) In relation to a work of joint authorship,—
(a) the reference in subsection (1)(a) to its being possible to ascertain the identity of the author shall be construed as a reference to its being possible to ascertain the identity of any of the authors; and
(b) the reference in subsection (1)(b)(ii) to the author having died shall be construed as a reference to all the authors having died.
Compare: Copyright, Designs and Patents Act 1988 s 57 (UK)