What is ‘prior art’ & what does a search involve?

Novelty, inventiveness and industrial applicability are the three key criteria for obtaining a patent. Whilst innovators might be certain that their idea is new and unique, prior art searches exist to ensure this is definitely the case.

This pre-qualification is an indispensable first step on the journey to patent protection. A thorough search can not only save a great deal of time and money, but also reveal valuable strategic opportunities for refining your inventions and patent applications.

What is prior art? #

Prior art, also known as state of the art or background art, is any existing global evidence that an invention or idea was already known to the public before the filing date of a patent application.

It can relate to a variety of things, including:

• Patents and applications – Existing patents (whether already pending, granted or expired).
• Articles – Content in any magazine, trade publication, news outlet, journal, academic paper, blog, website or even conference notes.
• Products and use – Anything already in use or on the market that proves your invention is not unique.
• Public disclosure – Talks, conferences, seminars, oral discussions and social media posts.

This final example is often associated with self-disclosure (or ‘inventor disclosure’). It is a common pitfall whereby the creator has discussed the innovation, even in brief, prior to filing an application.

Any kind of disclosure in the public domain can be fatal for your application, which is why the patent process always starts with a prior art search and reiterating the need for the invention to remain confidential before a patent application is filed.

Artificial intelligence, large language models and prior art #

The proliferation of AI has created many opportunities and risks in the IP space. Many innovators are using LLMs as a brainstorming or technical refinement tool, but this is ill advised.

Putting details of an unfiled invention into a public-use LLM like ChatGPT is potentially prejudicial to the novelty of an invention, and could render any later file patent application invalid.

This is because these models typically utilise user inputs for training and feedback purposes. Any inputted data is therefore non-confidential and in the public domain, destroying the novelty required for patentability.

What does not count as prior art? #

Prior art only includes publicly available information at the time the patent application was filed. Undisclosed documents, private communications and proprietary assets (such as unfiled prototypes) do not count.

A shift in the rules #

Historically, a competitor’s product would only ‘count’ as prior art if an expert was able to reproduce the invention without the need for experimentation or their own research. This was often known as the reproducibility rule.

However, following the landmark EPO decision G 1/23, the rules have changed.

In July 2025, the European Patent Office confirmed that a product can be prior art even if it cannot be reproduced. If it is commercially available, any technical information about the product can be used to challenge a patent.

What does prior art searching involve?  #

A prior art search involves uncovering all pre-disclosed information for the purposes of demonstrating the patentability of an invention.

This includes interrogating global patent databases (such as Espacenet and Patentscope) and scanning non-patent literature (such as journals, white papers and commercial product catalogues). This process uses many tools and techniques and can involve thousands of references.

Results from these searches will determine whether your idea or invention meets the novelty and inventiveness criteria to be granted a patent.

Why do I need a prior art search? What are the benefits? #

Most fundamentally, prior art searching ensures that innovators don’t waste time and money on applying for a patent for something that may already exist.

This is because evidencing novelty, inventiveness and industrial application is the fundamental basis for securing a patent. If any of these elements are already pre-existing in another application, product or within research, a patent will not be granted.

Given the costs of a UK patent application start from £405 at the very minimum and can easily range into thousands, patent searches can be a prudent financial decision.

But expense is not the only factor. Prior art searches uncover opportunities to tailor your application around existing technologies, revealing exactly what your patent application needs to focus on, communicate and contain.

This is perhaps the most strategically valuable aspect to patent searching. It gives you a clear picture of the competitive landscape and identifies ‘white space’ where no inventions currently exist, thus enabling you to tailor your inventions.

Searching can also highlight issues around ‘freedom to operate’ (FTO), so you avoid infringing on the rights of third parties before committing to further costs.

Can I do patent searching myself? #

Like many aspects of the patent process, it is possible to take a DIY approach to prior art searches. However, the risks often make it more cost-effective to seek the support of a search specialist.

A professional patent attorney will provide a thorough examination of all potential obstacles to your patent application’s viability and provide strategic advice to help you tailor your application for success.

At Murgitroyd, we offer the market’s premier IP search service.

Our patent search specialists collaborate with innovators taking their first steps towards protecting inventions in the UK and beyond, offering commercially-driven guidance aligned to your business aims and objectives.

Start your journey to patent protection #

Patents turn your ideas into legally-enforceable commercial assets. Step one of the entire process is an extensive and comprehensive prior art search.

Whatever your specialism or sector, we can support you in evaluating the novelty of your innovation, conducting the relevant searches and securing the protection your inventions deserve.

Our patent experts are ready when you are: talk to us today.