There are some very limited exemptions in the use of copyrighted material without first seeking the copyright owner's permission.
One exemption, for ‘fair dealing', allows use without permission for research or non-commercial purposes which do not infringe copyright, and sufficiently acknowledges the source. Another exemption under ‘fair dealing' is for use in criticism or review of published work.
The other main exemption, ‘substantial part', allows for inconsequential parts of copyrighted work to be used without the owner's permission. It should be noted that ‘substantial part' is not a quantitative term, i.e. it is not about how much of the work is used, as it covers the significant parts of a copyrighted work. Even small parts of a work could be deemed ‘substantial'. The quality and importance of what is being appropriated into the new artwork is more important that the quantity. There is no legally defined limit to what is ‘substantial'.
For more information and a practice-based look at these concepts, watch this film about artist David Mabb's appropriation of other artust's work from our ArtlawTV series.