Advocate General Yves Bot said that computer programs that have the same possible functions can co-exist without copyright being infringed but creators of the means by which the programs carry out those functions can obtain copyright protection for those methods.

In doing so he agreed with a provisional ruling by the UK High Court, which referred the case to the ECJ.

It is not possible to copyright ideas, only the expressions of those ideas. Bot's opinion is not binding on the ECJ but judges use the opinions in making their decisions and opinions are followed in a majority of cases.

"The functionalities of a computer program and the programming language are not eligible, as such, for copyright protection," Advocate General Bot said in his opinion.

"It will be for the national court to examine whether, in reproducing those functionalities in his computer program, the author of the program has reproduced a substantial part of the elements of the first program which are the expression of its author’s own intellectual creation," he said.

Bot published his opinion on a UK case between SAS Institute and World Programming Ltd (WPL). The UK High Court asked the ECJ to rule on the scope of copyright protection for software in the EU's Computer Programs Directive and Information Society Directive.

SAS claimed that WPL infringed its copyrights by developing a rival software program by using information contained in SAS software manuals. SAS wanted the ECJ to apply copyright protections to the functions of computer programs.

SAS makes programmes which enable customers to analyse data and write other programs within the SAS environment to carry out specific functions. WPL wrote a piece of software which would allow former SAS users to execute programs written in SAS's language without continuing to pay SAS for the use of its systems.

WPL's software emulated the SAS system in an attempt to ensure that computer code written in the SAS system would behave in the same way in its system, which WPL said is cheaper than SAS's.

The ECJ is hearing the case after a UK High Court judge referred questions to it about how EU law should be interpreted. The judge provisionally ruled in favour of WPL but acknowledged that there was sufficient doubt over how laws set out in the EU's Computer Programs Directive and Information Society Directive should be applied to merit a referral to the ECJ.

Under the Computer Programs Directive copyright protection is given to "the expression in any form of a computer program" but does not apply to "ideas and principles which underlie any element of a computer program, including those which underlie its interfaces".

The Directive also states that "the person having a right to use a copy of a computer program shall be entitled, without the authorisation of the rightholder, to observe, study or test the functioning of the program in order to determine the ideas and principles which underlie any element of the program if he does so while performing any of the acts of loading, displaying, running, transmitting or storing the program which he is entitled to do".

The Information Society Directive sets out rules on reproduction rights. Under the Directive EU member states "shall provide for the exclusive right to authorise or prohibit direct or indirect, temporary or permanent reproduction by any means and in any form, in whole or in part for authors, of their works".

Advocate General Bot said that the possible workings of a computer program and the language used to create it is not in itself copyrightable because they constitute ideas without "concrete expression". Ideas on their own are not copyrightable.

"The functionality of a computer program can be defined as the set of possibilities offered by a computer system, the actions specific to that program," Bot said in his opinion.

"In other words, the functionality of a computer program is the service which the user expects from it. In my view, the functionalities of a computer program cannot, as such, form the object of copyright protection under [the EU's Computer Programs Directive]," he said.

"Let me give a specific example. Where a programmer decides to develop a computer program for airline ticket reservations, that software will contain a multitude of functionalities needed to make a booking. The computer program will have to be able, in turn, to find the flight requested by the user, check availability, book the seat, register the user’s details, take online payment details and, finally, edit the user’s electronic ticket," he said.

"All of those functionalities, those actions, are dictated by a specific and limited purpose. In this, therefore, they are similar to an idea," said the opinion. "It is therefore legitimate for computer programs to exist which offer the same functionalities. There are, however, many means of achieving the concrete expression of those functionalities and it is those means which will be eligible for copyright protection."

Bot said that because the possible functions of computer programs is finite, allowing them to be copyrighted would stunt innovation.

"Creativity, skill and inventiveness manifest themselves in the way in which the program is drawn up, in its writing. The programmer uses formulae, algorithms which, as such, are excluded from copyright protection because they are the equivalent of the words by which the poet or the novelist creates his work of literature. However, the way in which all of these elements are arranged, like the style in which the computer program is written, will be likely to reflect the author’s own intellectual creation and therefore be eligible for protection," Bot said.

"To accept that a functionality of a computer program can be protected as such would amount to making it possible to monopolise ideas, to the detriment of technological progress and industrial development," he said.

Bot added that reproducing source code for the possible functions of a computer program could infringe copyright if the reproduction is "a substantial part of the expression of the functionalities of a computer program" regardless of the "nature and extent of the skill, judgment and labour expended in devising the functionality of a computer program". He said that it is the way that computer programs are written that will determine whether they are copyrightable.

"In order to determine whether a computer program is eligible for legal protection under copyright, account should be taken not of the time and work devoted to devising the program nor of the level of skill of its author but of the degree of originality of its writing," Bot said.

Bot said that software licensees are not allowed to observe, study or test the way computer programs work if that activity allows the program to be copied and copyright-protected information within it accessed.

"The expression ‘any of the acts of loading, displaying, running, transmitting or storing the computer program [which the person having the right] is entitled to do’ relates to the acts for which that person has obtained authorisation from the rightholder and to the acts of loading and running necessary in order to use the computer program in accordance with its intended purpose," Bot said in his opinion.

"Acts of observing, studying or testing the functioning of a computer program which are performed in accordance with that provision must not have the effect of enabling the person having a right to use a copy of the program to access information which is protected by copyright, such as the source code or the object code," he said.

Bot said that the reproduction of instructions contained in manuals could be infringing, but only if the "elements" are reproduced in a way that express the "author's own intellectual creation". He said it was up to the High Court to determine whether WPL had infringed on SAS' rights in this way.

In its ruling last year the High Court said that while copyright law protected the source code of software programs, it did not prevent one company writing software that copied the way another program worked.

Mr Justice Arnold had considered a case involving budget airline easyJet and developer Navitaire when coming to his provisional ruling. In that case the judge ruled that the EU's Computer Programs Directive meant that copyright in computer programs did not protect programming languages, interfaces or functionality.

In the easyJet judgment in 2004 Mr Justice Pumfrey ruled that the EU's Computer Programs Directive meant that copyright in computer programs did not protect programming languages, interfaces or functionality.

SAS argued that this was an incorrect interpretation of the Directive. Mr Justice Arnold did not agree but said that there was enough doubt, as expressed by Mr Justice Pumfrey in 2004, that the ECJ should be asked to clarify the law.