Insights High Court finds former employee had copied source code from program belonging to the former employer after he had left employment


Productivity-Quality Systems Inc (PQS), a US company, develops software to assist with quality assurance in manufacturing. Before 2015, PQS carried on business alongside PQ Systems Europe Ltd (PQE) (together PQ).

Jeff Aughton was employed by PQE as a software developer from 1989 until 15 May 2015.

In around 2006/2007, Mr Aughton was tasked with re-writing PQ’s statistical process control software (SPC), which is an analytical technique for improving industrial processes, and its gauge management software, which monitors the data and produces charts, in a programming language called VB.NET. At the same time, another developer employed by PQ produced an alternative version written in Windows Presentation Foundation (WPF).

After Mr Aughton had mostly completed his work, PQ decided to go forward only with the WPF version. Mr Aughton considered this to be a serious mistake and requested, and was granted, permission to leave the project. However, while working on a different project for PQ, Mr Aughton also carried on developing an SPC program in VB.NET, which he called “ProSPC”. He said that he spent about 50 working days of his own time on it during 2007/2008, then set it aside before picking it up again in about 2012.

Once he had left PQ’s employment in 2015, Mr Aughton started work on what he said was an entirely new SPC program for creating charts by tapping into an existing data collection system, written in VB.NET. He called the program “InSPC”. He later re-wrote the program in a new language, C#, to produce InSPC v2.

PQ issued proceedings against Mr Aughton for copyright infringement and breach of confidence in relation to both versions of InSPC. PQ, which claimed ownership of ProSPC, said that Mr Aughton had copied InSPC v1 from ProSPC and had copied again when creating InSPC v2 from InSPC v1.

Mr Aughton denied this and contended that: (i) the copyright in ProSPC belonged to him because it was written as a hobby project outside the course of his employment; and (ii) in any event he did not copy from ProSPC when writing either version of InSPC.

Mr Justice Zacaroli noted that in most cases questions of copying can be resolved by comparing source code. However, here, that was not possible as Mr Aughton had deleted the source code for both ProSPC and InSPC v1. Only the object code was available for the two programs, which PQ sought to decompile for the purposes of the case.

Zacaroli J found that on the facts and evidence, Mr Aughton had written ProSPC in the course of his employment with PQ, meaning that it belonged to PQ. There was evidence of similarities between the source code of another of PQ’s programs and the decompiled object code of ProSPC that could only be explained by copying. Further, writing SPC software was a core part of PQ’s business and Mr Aughton’s work in writing ProSPC was undoubtedly integral to that business. In addition, it could be inferred that when writing ProSPC Mr Aughton intended for it to be of at least potential use to PQ. Finally, Zacaroli J concluded that whilst Mr Aughton had written ProSPC at home, he had done so on his work computer rather than his own personal computer. Accordingly, the copyright and the confidential information belonged to PQ.

As for whether InSPC v 1 had been copied from ProSPC, the expert witnesses agreed that there was evidence of similarities between the two. Zacaroli J found that the only explanation for coincidences in the similarities was that they had been copied from ProSPC.

As for whether a substantial part had been copied, Zacaroli considered there were several reasons to find that it had, including: (i) the circumstances in which Mr Aughton had retained ProSPC after he left PQ; (ii) the circumstances in which he had deleted ProSPC; (iii) the circumstances in which he had deleted InSPC v1; and (iv) his attempts to downplay the utility of ProSPC. Zacaroli J also said that Mr Aughton’s own account of these factors was inconsistent and not credible.

As for the question of indirect copying from ProSPC in relation to the creation of InSPC v2, Zacaroli J inferred from the facts and evidence that Mr Aughton had started rewriting InSPC in C# after he had received the letter before action from PQ. Overall, on the facts and evidence, Zacaroli J found that it was more likely than not that Mr Aughton had copied from at least a substantial part of the source code for InSPC v1 when writing InSPC v2.

As for the breach of confidential information claim, it was clear from Mr Aughton’s contract of employment that he was prevented at any time (whether during his employment or afterwards) from using or disclosing to any person any “Confidential Information” (which includes source code), except in the proper course of his duties or where use or disclosure was authorised by PQ or required by law, where the information was already in the public domain or where it was protected within the meaning of s 43A of the Employment Rights Act 1996. None of these exceptions applied to anything done by Mr Aughton after he left PQ in 2015.

Accordingly, Zacaroli J found that Mr Aughton had infringed PQ’s copyright and breached his contractual duties of confidentiality in writing both InSPC v1 and InSPC v 2. Damages will be assessed at a later date. (PQ Systems Europe Ltd v Jeff Aughton [2023] EWHC 581 (Pat) (22 March 2023) — to read the judgment in full, click here).