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Open Source Licensing and Intellectual Property in the UK | LegalDocuments.co.uk

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Written by Brad Askew Solicitor (non-practising)
Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice.
Updated June 2026 · England & Wales
Open source software sits behind a huge proportion of what British businesses build, ship and rely on every day. Yet the licensing that governs it is often treated as an afterthought, right up until a release is blocked, an investor flags a due diligence concern, or a customer contract demands a full bill of materials. In this guide I've tried to set out, in straightforward terms, how open source licences interact with UK copyright law, which licence families you are most likely to encounter, and the practical questions founders and developers should be asking before they paste code into production. It isn't a substitute for talking to someone about your specific project, but it should give you a working grounding.

Overview

Open source licensing is the mechanism by which a copyright holder permits others to use, study, modify and share their software, usually on terms published alongside the code itself. Under the Copyright, Designs and Patents Act 1988, software is protected as a literary work the moment it is written in the UK.

The author retains copyright by default, and anyone wishing to copy or adapt that code needs permission. An open source licence is how that permission is granted at scale, without every user having to negotiate a bespoke agreement. What makes a licence 'open source' rather than simply 'free to read' is the combination of rights it hands over: the ability to run the software for any purpose, inspect its inner workings, build on it, and redistribute the result.

Different licences attach different conditions to those rights, and the choice of licence can significantly affect what you are allowed to do with the resulting product, how you credit contributors, and whether you must release your own modifications.

Key steps

  1. Map what you are already using. Before you think about licensing your own code, get visibility on the open source components already present in your stack. Dependency scanners, software bills of materials and manual audits all help. You cannot comply with terms you don't know exist, and acquirers will ask.
  2. Read the licence text, not the summary. Short descriptions like 'permissive' or 'copyleft' are useful shorthand but they hide material differences. Obligations around attribution, patent grants, network use and source disclosure vary between licences that look similar at a glance. Spend time with the actual wording.
  3. Decide what you want to protect and what you want to share. If you are releasing your own project, the licence you pick signals your intent to the community and to commercial users. A permissive licence encourages broad adoption; a copyleft licence keeps derivatives open. Neither is wrong, but the choice is hard to reverse once others build on your code.
  4. Check compatibility before combining codebases. Not every open source licence plays nicely with every other one. Mixing code released under strong copyleft terms with code released under more permissive or proprietary terms can create conflicts that force you to relicense, remove components or open-source work you intended to keep closed.
  5. Document contributions and keep records. If you accept outside contributions, a contributor licence agreement or a developer certificate of origin helps establish that you have the rights you need. Keep notices, licence texts and change histories intact when you redistribute, because most open source licences require it.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £149.

Common questions

Q Is open source software really free to use commercially in the UK?
In most cases yes, but 'free' refers to freedom, not the absence of obligations. UK businesses can generally use open source software in commercial products, provided they comply with the terms of the relevant licence. Those terms may require attribution, inclusion of the original licence text, or in some cases the release of source code for modifications you distribute.
Q Does UK copyright law apply to open source code?
Yes. Software is protected as a literary work under the Copyright, Designs and Patents Act 1988, and that protection applies whether the code is proprietary or open source. An open source licence does not remove copyright; it sets out the conditions on which the copyright holder permits others to use the work. Breaching those conditions can amount to copyright infringement.
Q What is the difference between permissive and copyleft licences?
Permissive licences, such as MIT or Apache 2.0, let you reuse code with minimal obligations, often just attribution and retention of the licence notice. Copyleft licences, such as the GPL family, require that derivative works distributed to others are released on the same terms. The practical consequence is that copyleft can flow through into your own code, whereas permissive licences generally do not.
Q Can I mix open source code with my proprietary software?
Often yes, but it depends on which licences are involved and how the code is combined. Permissive licences usually allow this without difficulty. Stronger copyleft licences can require you to release your combined work under the same terms if you distribute it. Linking, static compilation and network use are all treated differently by different licences, so careful analysis matters.
Q Do I need to publish my source code if I use GPL software internally?
Generally the GPL's source-sharing obligations are triggered by distribution to third parties, not purely internal use. If you run modified GPL software inside your own organisation without handing copies to outsiders, the obligation to publish source typically doesn't arise. The AGPL is different, as it treats network access as a form of distribution. Check the specific licence carefully.
Q Who owns the copyright in contributions to an open source project?
By default, each contributor retains copyright in what they wrote, and licenses it to the project on the terms set out by the project. Some projects ask contributors to sign a contributor licence agreement assigning rights or granting a broader licence to the project maintainer. This affects who can enforce the licence and who can relicense the project later.
Q What happens if we breach an open source licence?
Breach of an open source licence can terminate your rights to use the code and expose you to claims of copyright infringement. Many licences include automatic termination clauses, though some offer a cure period. Practical consequences often include reputational damage, forced code releases, and awkward conversations with customers, investors or acquirers during due diligence.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £149.

Sources

This guide is based on primary UK law and official guidance.

Brad Askew, Solicitor (non-practising)

Written & reviewed by

Brad Askew Solicitor (non-practising)

Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice. LegalDocuments.co.uk is not a law firm and does not provide regulated legal advice.

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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.