UK divisional patent applications: Don’t delay

Patent applicants should take note of changes to how the UK calculates the compliance date for divisional applications, explain Parminder Lally and Debora Dorn.

In the UK, a patent application must be in order for grant by the end of a “compliance period” and, if it is not, the application is deemed refused.

The compliance period is defined in the UK Patents Act as the later of: (i) four years and six months from the earliest priority date or if no priority is claimed, from the filing date, or (ii) twelve months from the date of the first substantive examination report. This is a straightforward calculation on a first/parent UK patent application, but is a bit more complex for divisional applications. The UK Intellectual Property Office (IPO) is now changing how it calculates the compliance date for divisional applications.

The new practice, which will come into effect on May 1, 2023, may reduce the amount of time available to prosecute a divisional application, so it is advisable to file divisional applications in the UK, if required, at the earliest opportunity.

In this article, we first provide a summary of the current and new practices.

For divisional applications that are filed a long time before the end of the compliance period, nothing is really changing. However, for divisional applications filed “late”, ie close to the end of the compliance period, things are changing. Therefore we also provide, for those interested in knowing more, a detailed explanation of how the change in practice may impact the actions required to file and prosecute a “late” divisional application.

Current practice: A summary

Currently, the compliance period for a UK divisional application is the same as the parent application’s compliance period, except if the parent’s compliance period has been extended. It is possible to extend the compliance period of the parent application by two months (and potentially further, but any such further extensions are discretionary). This extension may be obtained when more time is needed to place the application in order for grant.

Currently, when the parent’s original compliance period has been extended, the UKIPO considers the parent’s extended compliance period to be the un-extended compliance period for the divisional application, if the extension is obtained before the divisional is filed.

As a result, under the current practice, the compliance period of a divisional application could end later than the compliance period on the parent application. This is because the divisional application’s compliance period can itself be extended by two months, for the same reason.

New practice: A summary

Under the new practice, which comes into effect on 01 May 2023, a UK divisional application’s un-extended compliance period will be the same as the original un-extended compliance period of the parent, even if the parent’s compliance period has been extended before the divisional is filed.

Since divisional applications must be filed when there are at least three months remaining in the compliance period, it will be necessary to think more carefully if a divisional application is to be filed “late”.

More details about this are provided below. Importantly, this change also applies to divisional applications that themselves derive from a divisional application—they are assigned the same un-extended compliance period as the original parent application as well.

Additionally, the compliance period of the divisional application itself can no longer be extended beyond the extended compliance period of the parent application, which effectively means that there will be less time to prosecute divisional applications towards grant under the new practice.

However, the change in practice will have no impact on divisional applications filed on or before 28 April 2023 – these will be given a compliance period based on current practice. Thus, to benefit from the more generous current compliance period calculation, you may wish to file new divisional applications by this date.

After May 1, 2023, it will be useful to file new divisional applications at the earliest opportunity, to ensure there is sufficient time to prosecute the application before the compliance period (plus any extensions) ends. In both cases, you may wish to file divisional applications if, for example:

• The claims of the parent application were considered to relate to multiple inventions – the divisional application allows you to pursue a patent for one of the inventions that had to be deleted from the parent;
• There is subject matter in the description of the patent application that is not covered by the claims of the parent application, and this subject matter is commercially important to patent;
• You wish to limit the activities of competitors, and have content in the application that describes features of competitor products.

We will now explain the current and new practices in more detail.

Current practice: A detailed explanation

The deadline for filing a divisional application (shown in red in all scenarios in figure 1) is three months before the end of the parent’s compliance period (see scenario A). There are two ways to extend this deadline.

One way is by obtaining a discretionary extension to the deadline for filing a divisional application, as shown in scenario B, by the dashed orange line.

This method essentially shifts the deadline to file a divisional application to one month before the end of the compliance period. This may not be enough time to get the divisional application in order for grant—we explain below how this is currently dealt with. We note that since the extension of scenario B is discretionary, it is normally only granted if it can be shown that the circumstances are exceptional, and the applicant has been properly diligent.

Figure 1: Obtaining a discretionary extension to the deadline of a UK divisional application (current practice).

Another way to extend the deadline is by obtaining an extension to the parent’s compliance period, as shown in scenario C by the black line (figure 2). In contrast to the extension of scenario B, the two-month extension shown in scenario C (black line) can be obtained as of right.

This means the compliance period, and thus the deadline for filing a divisional application, can always be extended in this manner.

Figure 2: Obtaining an extension to the parent patent’s compliance period (current practice).

As shown in scenario D (figure 3), a further discretionary extension (indicated by the dashed black line) is available to extend the parent’s compliance period. However, to obtain this extension, again, it must be shown that the circumstances are exceptional and the applicant has been properly diligent.

The compliance period of the divisional application that is filed in each of scenarios A to D is shown in blue, and in each of these scenarios, this is the same compliance period as that of the parent application.

Importantly, under the current practice, the divisional application inherits the parent’s compliance period as its un-extended compliance period, even if the parent’s compliance period has been extended.

This means that further extensions to the divisional application’s compliance period are possible. This is shown in scenario E, by the blue lines. This means that a divisional application’s compliance period could currently end up to eight months after the parent’s original compliance period.

The first of these extensions (solid blue arrow) is available as of right, meaning that under the current practice, a divisional application’s compliance period can be extended two months past its parent’s compliance period as of right. 

Figure 3: Obtaining a further discretionary extension to the parent patent’s compliance period.

New practice: A detailed explanation

Under the IPO’s new practice, a divisional application’s compliance period is the original unextended compliance period of its parent application (figure 4).

The divisional compliance period can be extended, if further time is required to put the application in order for grant, in the same way as extensions to the compliance period can be obtained for the parent application.

Scenarios B’, C’, F1 and F2 show how the parent’s compliance period, the deadline for filing a divisional application, and the divisional’s compliance period are moved along in time under the new practice when applying for the various extensions described above. 

Scenarios B’ and C’ show, respectively, how even when the parent application’s compliance period is extended via an as of right extension and via a discretionary extension, the compliance period of the divisional application is unchanged. It is possible (and indeed necessary in at least scenario C’) to request the same types of extensions to the divisional application’s compliance period to allow sufficient time to prosecute the divisional application.

Figure 4: Obtaining an extension to a divisional patent application’s compliance period under the new practice.

Scenario E described above will no longer be possible under the new practice. If a divisional application is granted the same extensions to the compliance period as its parent, it will have the same extended compliance period as its parent. This is the latest point in time to which the divisional application’s compliance period can be extended under the new practice.

As noted above, divisional applications can only be filed when there are at least three months remaining in the compliance period.

The latest point at which a divisional application can be filed under the new practice is dictated by the compliance period it will be assigned. It will not be possible to put the divisional application in order for grant if there is no time left in its compliance period, and therefore it is not possible to file a divisional application when the divisional’s compliance period has expired.

At the same time, it is only possible to apply for an extension to the divisional’s compliance period before the end of the as of right extension (as in the UK, extensions can be obtained retrospectively). 

Looking at scenario F1 (figure 4), if the end of the compliance period for an unfiled divisional is April 1 and that deadline is approaching, it will be necessary to first obtain all possible extensions (as of right and discretionary) on the parent application so that the divisional application can be filed.

With all these extensions, as shown in scenario F1, the divisional deadline is three months before the parent’s fully extended compliance period, ie, May 1. However, if this deadline has been missed, it is possible to obtain an extension to the deadline to file the divisional application.

As the divisional application must be filed within two months of the end of the divisional’s original compliance period, a full two-month extension to the deadline to file the divisional cannot be obtained (as this would shift the filing deadline to July 1).

This means, as shown in scenario F2, that the latest point at which a divisional application can be filed under the new practice is two months after its parent’s compliance period has expired! In scenario F2, the same extensions to the compliance period of the parent would have to be requested for the divisional application, so that there is time left to prosecute the divisional application towards grant. 

Figure 5: Divisional application extension scenarios under the new practice.

Parminder Lally is a senior associate at Appleyard Lees IP. She can be contacted at: parminder.lally@appleyardlees.com

Debora Dorn is a trainee patent attorney at Appleyard Lees IP. She can be contacted at: debora.dorn@appleyardlees.com

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