LAST REVIEWED: OCTOBER 2026
By Dr Ritchie Lewis Daniel, Chartered Patent Attorney and European Patent Attorney
A startup does not need a finished product before filing a patent application. The useful question is whether the invention is sufficiently developed to describe properly, and whether the features being protected are likely to remain important as the product develops.
File too early and the application may miss the mechanism that eventually makes the product work. Wait too long and a demonstration, launch or competing application may affect the opportunity to obtain protection.
Short on time?
- Assess what is settled: A finished product is not essential. You need enough technical substance to explain how the invention works, with a clear reason to protect those features.
- Check the next disclosure: Review presentations, demonstrations and user trials before sharing technical information. Check that the application describes the invention you plan to reveal.
- Allow for further development: Different features can be ready for filing at different times. New technical detail may need another application and may have a later priority date.
- Understand the timetable: A first filing normally starts a 12-month priority period. Applications are usually published around 18 months from the earliest priority date.
- Make waiting an active decision: Agree a review date and development milestones. Reassess sooner if disclosure plans or competitive risks change.
How developed does the invention need to be?
When considering a mechanical invention, I first look at how far the engineering has been resolved. Is the fundamental mechanism understood, or could testing and manufacturing work still change the design substantially?
Useful questions include:
- Can the team explain how the invention achieves the intended result?
- Which features are essential, and which are still being explored?
- What alternatives have been considered?
- What have testing and confidential user feedback established?
- Could manufacturing, robustness or usability requirements change the mechanism?
A working prototype can help answer those questions, but is not a legal prerequisite. Drawings and a sound technical explanation may be enough. The application must provide sufficient information for a person skilled in the relevant field to carry out the invention. Describing the desired result without explaining how to achieve that result may be inadequate.
If the team is still deciding between fundamentally different mechanisms, further confidential development may improve the value of a filing. If the inventive mechanism is settled and likely to remain in the product, waiting for every manufacturing detail may serve little purpose. Whether the invention is new and inventive also needs assessment; technical readiness alone does not establish patentability.
Example: a folding personal transport device
Consider a hypothetical folding personal transport device. The prototype works, and the team has developed the folding mechanism and considered alternative arrangements. The mechanism is expected to remain central to the product.
The device still needs work before manufacture. Weight, wiring routes, component packaging and balance when carried may change. Those tasks need not prevent an application directed to the folding mechanism, provided the application explains that invention adequately.
If manufacturing work instead requires a different folding arrangement, the original filing may be less useful. That possibility belongs in the filing decision. Later development may also produce further inventions worth protecting separately.
Different features of the same product can be ready for filing at different times.
What will the next demonstration or pitch reveal?
Before a launch, investor pitch or user trial, review what people will see, hear and receive. Relevant material includes slides, videos, drawings, answers to questions and any product or prototype handed over.
A presentation describing a benefit can reveal less than a demonstration showing the mechanism. Giving someone a product to inspect, test or dismantle may disclose more than a controlled demonstration. A sale or other unrestricted supply may make the product itself available as prior art. The EPO decision G 1/23 confirms that a marketed product is not excluded from prior art simply because its internal structure cannot be analysed and reproduced. Concealing internal workings does not necessarily make a demonstration safe either: visible features and operation may reveal important technical information.
An NDA can help establish confidentiality, but the arrangements must cover the intended recipients and activity. A trial should address what participants can use, share, photograph or pass to others. Do not assume that an investor meeting is confidential simply because attendance is limited.
For UK and European patent protection, there is no general grace period for your own public disclosures. If a planned disclosure would reveal the invention, the usual approach is to file an adequate application first, postpone the disclosure or change what will be shared.
Where the design is still evolving, compare the planned disclosure with the proposed application. A filing receipt does not mean every feature shown at the event has been protected. Allow time for drafting and review before the event.
If appearance is commercially important, consider registered design protection alongside patents. The two protect different aspects of a product.
What if information has already been disclosed?
Seek advice promptly and retain evidence of what was shared, when, with whom and under what confidentiality arrangements. An earlier disclosure does not necessarily prevent protection for every later development, but the effect needs assessment.
Limited exceptions may apply to certain disclosures resulting from a breach of confidence or abuse. The UK provisions and European provisions differ. Strict conditions apply, including a six-month period measured against the relevant application's filing date, rather than its priority date. These exceptions should not be treated as a fallback for a planned disclosure, and any overseas filing plans need urgent review too.
What if the product changes after filing?
Further development is normal. Review significant changes against the application rather than assuming the first filing covers the final product.
New technical subject matter cannot simply be added to the existing UK or European application: amendments cannot extend beyond the original disclosure. A further application may be appropriate, sometimes described informally as a top-up filing.
A later application filed within the normal 12-month priority period may claim priority from the first application for the same invention adequately disclosed there. New features or combinations do not automatically receive that earlier date merely because the original claims were broad enough to cover them.
For example, the first application might adequately describe the folding mechanism but say nothing about a later-developed locking arrangement. Protection directed to that new arrangement may have a later date. Any disclosure before the later filing then needs checking.
This is why filing should remain connected to product development, rather than being treated as a task completed once for the whole product.
What timetable does the first filing start?
Two dates deserve attention from the outset:
- The normal 12-month priority deadline. Corresponding overseas or international applications generally need to be filed within this period to claim the first filing's priority. Markets, manufacturing locations, competitors and budget should inform those decisions.
- Publication, usually around 18 months from the earliest priority date. If no priority is claimed, the period runs from filing. Publication makes the technical disclosure available to competitors, potentially before product launch.
An early filing can therefore bring later spending decisions and publication forward before the business has much commercial evidence. Consider whether the likely publication date fits the development and launch plan, alongside the risks of waiting.
An application can be withdrawn in time to prevent its publication, before the patent office completes the relevant preparations. Withdrawal does not undo a public demonstration or restore novelty lost through disclosure. Another application claiming priority may still make the earlier material public. Refiling with a later date can also expose the invention to intervening disclosures and applications. Any withdrawal and refiling strategy needs specific advice.
Your own earlier applications can also become prior art against later filings. Depending on their dates and publication, they may affect novelty alone or both novelty and inventive step. The relationship between the applications needs checking before refiling or filing improvements.
If you decide to wait, what should trigger a review?
Waiting can be sensible where the engineering is changing and confidentiality can be maintained. Agree a review date and specific triggers, such as:
- Selection and verification of the main mechanism.
- Manufacturing work that confirms or changes the design.
- An approaching demonstration, user trial, crowdfunding campaign or launch.
- Discussions with investors, manufacturers or collaborators requiring more technical detail.
- Changes to the team or confidentiality arrangements.
- Evidence of competitor activity relevant to the invention.
Confidential development does not stop another business independently filing first. Nor does a search showing no relevant published application establish that competitors have not filed: applications normally remain unpublished for a period.
For university spin-outs, publication plans also need coordination. Thesis access, papers, conference presentations and collaboration obligations can bring the decision forward.
What should you prepare for a filing discussion?
Bring drawings or sketches, an explanation of how the invention works, the alternatives considered and a clear account of what remains uncertain. Include the next disclosure dates and any information already shared outside the team.
Identify who devised the inventive features and who should own the application. Founder, employee, contractor, university and collaboration arrangements may need checking. Inventorship and ownership are separate questions.
Finally, explain the commercial purpose. Which product features matter to customers? What would useful protection make harder for competitors? What expenditure can the opportunity justify?
A pending application is not a granted patent, and a filing made for fundraising is useful only to the extent that its technical content and potential protection support the business. See preparing your IP portfolio for investment and UK patent application costs.
RIDAN IP provides patent drafting and filing advice for engineering businesses and hardware startups. A discussion about the technology, what remains unresolved and the next planned disclosure can help identify the appropriate next step.
General information only. This article focuses on UK and European patent considerations and does not constitute advice on any particular circumstances. The appropriate approach depends on the invention, disclosures, ownership, territories and commercial objectives.