At first instance  RPC 1 Arnold J held that copyright does not protect the functionality of computer programs or programming languages as such. In having replicated the functionality of SAS’s data processing and analytical software programs, World Programming had not infringed any copyright belonging to SAS, whether in the source code, or in manuals describing that functionality in details.
In the development of its own program, World Programming had also used copies of the SAS’ Learning Edition to interrogate functionality. Such interrogation was said to be in breach of the licence terms under which World Programming had purchased the Learning Edition. Having referred questions to the CJEU (C-406/10), it was further held by Arnold J.  RPC 17 that the defence based on Article 5(3) of the Software Directive applied. Even if the use of Learning Edition by World Programming fell outside the terms of the SAS’s licence, there was no infringement of the copyright in it, for the purposes of ascertaining functionality.
The appeal was brought against the order of Arnold J. Giving the judgment of the appellate court, Lewison LJ, with whom Vos and Tomlinson LJJ agreed, upheld the judgment of the court below. A computer program’s functionality does not amount to a form of expression – it is an idea and so not the subject of copyright protection, whether under the Computer Program Directive, insofar as the source code is concerned, or the Information Society Directive, so far as the manuals are concerned.
Further, the Court of Appeal held that the CJEU had been clear in its guidance that use of software outside the terms of a licence does not preclude reliance on the Article 5(3) defence. It followed that the licence terms were invalid in so far as they prohibited World Programming from doing what they had done. The first instance judgment was also upheld in this regard.