Under section 16(3) of the Copyright, Designs and Patents Act 1988, infringement will be found if there is copying of the work as a whole or any substantial part of it.

The judge identified the copied features as: the combination and relation of flowers and stripes, the manner in which they were painted, and the “resist effect”.

On appeal, RWT challenged the judge's finding that the copied features formed a substantial part of the Ixia design.

The House of Lords allowed DGL's appeal, finding no reason to interfere with the judge's decision.

A writer for the European Intellectual Property Review explained that while he did not explicitly state it, Lord Hoffmann provided a new test for whether a substantial part of the original work was copied.