An assignment of copyright is an outright transfer of some or all of the rights of a copyright owner. S. 90 (2) of the Copyright, Designs and Patents Act 1988 provides that an assignment may be limited to one or more, but not all, of the things the copyright owner has the exclusive right to do, or to part, but not the whole, of the period for which the copyright is to subsist. S. 91 (1) permits authors or others who would become first owners of copyrights ("prospective owners") that will or may come into existence in respect of a future work or class of works or on the occurrence of a future event ("future copyrights") to agree to assign such future copyright (wholly or partially) to another person.
S. 90 (3) of the CDPA provides that an assignment of copyright is not effective unless it is in writing signed by or on behalf of the assignor. However, a copyright, like any other species of property, can be held on trust. A trust can come into being impliedly or by operation of law as well as expressly. A company that commissions a graphic artist to do some art work for it is usually beneficially entitled to the copyright in the work as is a party to a joint venture as in IBCOS Computers Ltd. v Barclays Mercantile Highland Finance Ltd.  FSR 275 and Lakeview Computers Ltd. v Steadman and others(1999) CA. unreported 28 November.
Moral rights are not assignable (s.94 CDPA). One of the occasions upon which the right of paternity may be asserted is upon an assignment of copyright. It may be done by including a statement that the author or director asserts his right to be identified in relation to the work into the assignment (s.78 (2) (a) CDPA).