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  • Writer's pictureRosie Burbidge

Can you prove copyright infringement of software without seeing the source code?

Updated: Oct 30, 2023

A recent judgment from Mr Justice Zacaroli concerned the copying of software used in quality assurance manufacturing. The judge found copyright infringement and breach of confidence (PQ Systems Europe Ltd & Anor v Aughton & Anor).

The case was brought by Productivity-Quality Systems (PQ) against its former employee, Jeff Aughton, and his new company. In 2017, PQ discovered that Mr Aughton was supplying software (known as InSPC v1) to a US company, CyberMetrics. Mr Aughton had worked on ProSPC as a software developer until his resignation from PQ in 2015.

PQ claimed the InSPC v1 software had significant functional similarities to its own products (including a program known as ProSPC). It sued CyberMetrics in the US and the proceedings were settled on confidential terms. It then brought this action against Mr Aughton in the UK.

What was unusual about this case was that it was not possible to compare source code, because Mr Aughton had deleted the source code for both ProSPC and InSPC v1. Only the object code was available, so PQ’s case was based on circumstantial evidence.

Ownership of copyright and confidential information

The judge rejected Mr Aughton’s case that he owned the copyright in ProSPC as he wrote it from scratch, as a hobby project on his own computer, and found that it was written in the course of his employment.

Zacaroli J noted that “since writing SPC software was a core part of PQ's business, Mr Aughton's work in writing ProSPC was undoubtedly integral to that business” and he routinely worked from home, including at evenings and weekends. The software was also written using resources licensed by PQ. The judge additionally found that Mr Aughton had admitted that he wrote the software in the course of his employment in 2013.

Evidence of copying

The analysis of copying focused on similarities between the decompiled code of the two programs, once it was split into enums (a list of data included in source code, often with corresponding reference numbers assigned to them), methods (defined procedures) and properties (values which can be obtained, or set).

The judge found that “the explanation for the coincidences in the ordering and numbering of the chart types, as between the two programs, is that the ChartTypeEnum in InSPC v1 was indeed copied from ProSPC.”

In circumstances where Mr Aughton’s evidence was that he made no reference to ProSPC, but wrote InSPC v1 from scratch, he was not telling the truth and that undermined the credibility of his denial of copying more generally: “it is often identity of trivial matter that traps a copyist.”

Based on the “totality of the evidence” the judge was satisfied that a substantial part of InSPC was copied from ProSPC. This included expert evidence that the similarities indicated copying as well as the circumstances of Mr Aughton retaining ProSPC and later deleting the source code. The judge said:

the circumstances are such that I can and do draw the adverse inference that Mr Aughton has not retained the source code for InSPC v1 because it would have been unhelpful to him and CyberMetrics in defending PQ’s actual or threatened claims.”

The judge also found that Mr Aughton wrote a second program called InSPC v2, in C#, by copying at least a substantial part of the source code of InSPC v1. Whether or not he used an automatic translator to do this did not affect the finding.

Practical takeaways

As often happens in litigation involving former employees, this dispute involved strong feelings and allegations on both sides. In determining factual issues relating to when, why and how certain events happened, the judge generally preferred the claimant’s evidence.

Indeed, on a number of points, he found that Mr Aughton (who represented himself) was unreliable or untruthful, and that the evidence of his expert witness (Mr David Dufour) was unconvincing.

In cases such as this that hinge on detailed analysis of evidence, the advice of specialist solicitors and barristers will help identify and address potential issues in the arguments. While there will be a cost involved, it is likely to be well worth it to secure a successful outcome or a favourable settlement.

To find out more about the issues raised in this blog contact Rosie Burbidge, Intellectual Property Partner at Gunnercooke LLP in London -

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