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Compliance Periods: Changes for UK Divisional Applications from 1 May 2023

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The Patents Rules 2007 (as amended) (‘PR’) set out the detailed procedures under the Patents Act 1977 (‘UKPA’). Rule 30 PR is titled ‘Period for putting application in order’ and is otherwise known as the compliance period, which is the time period by which a patent application needs to comply with the UKPA.

Compliance Period for UK Divisional Applications:

The compliance period is calculated as the later of either four years and six months from the priority date or twelve months from the date of the first substantive examination report (s.18 UKPA). The ‘later of’ caters for cases where the s.18 report issues after 3.5 years, in which case the applicant has additional time to complete prosecution of their application.

Extension of Compliance Period:

The compliance period can be extended in two-month tranches under rules 108(2) and 108(3) PR which relate to an extension as of right and a discretionary extension. The compliance period is also automatically extended where an adverse decision on a substantive matter is given less than 28 days from the end of the compliance period. In this case, the applicant will have 28 days (plus any extension granted by the Courts) from the date of the decision to appeal the decision.

UK Divisional Applications:

A divisional application, under s.15(9) UKPA, is an application that relates to subject matter that is divided out from a ‘parent’ application to form a separate application. This may be done for various reasons, including overcoming a plurality of invention objection raised by a Patent Examiner under s.14(5)(d) UKPA. The subject matter of the divisional application must have been present in the parent application, but it may be different from the subject matter of any other divisional applications filed from the same parent application.

Timing of Divisional Applications:

Divisional applications must be filed before the parent application is granted, and at least 3 months before the expiry of the compliance period of the parent application. The parent application cannot have been refused, or withdrawn before the divisional is filed.

New Practice for Compliance Periods:

Starting 1 May 2023, the UK Intellectual Property Office (‘UKIPO’) will be changing its approach to calculating compliance periods for divisional patent applications. This change will effectively reduce the time applicants have to file and prosecute divisional applications.

Under the new practice all divisional applications will be accorded the un-extended compliance period of their original parent application.

This means that divisional applications will no longer inherit ‘extended’ compliance periods of parent application as their own un-extended compliance periods. Instead, all divisional application will be accorded un-extended compliance periods of original parent applications.

This change will only affect divisional applications filed on or after 1 May 2023. Applications already granted will not be affected. Divisional applications filed on or before 28 April 2023, will still be accorded a compliance period according to existing practice.

Impact and Timing:

Under the new UKIPO practice, the latest an applicant can file a divisional application is up to one month before the expiry of the un-extended compliance period of the parent application, assuming a two-month extension as of right under rule 108(2) PR to the compliance period.

However, in the instance that the applicant relies on a discretionary extension under rule 108(3) PR, the latest a UK divisional application can be filed would be two months after the expiry of the un-extended compliance period of the parent application. It’s important to note that discretionary extensions are rarely granted, and the applicant would need to demonstrate exceptional circumstances to the UKIPO.

As a result of this change, sequential or cascading divisional applications may be more constrained by time limits. Each divisional application will have the same un-extended compliance period as the original parent application.

For example, a second-generation divisional application must comply with the un-extended deadline of the grandparent application, rather than that of the first-generation divisional application from which it was filed.

If the compliance period of a parent application is extended following requests under rules 108(2) and 108(3) PR, a divisional application will still inherit the original and un-extended compliance period of the parent application. Therefore, the applicant would need to request extensions to the divisional application separately because any extensions to the compliance period of the parent application will not be automatically ‘passed down’ to divisional applications.

The UKIPO advises that when an applicant requests an extension to the compliance period of an application to file a divisional application, it’s generally necessary and expected to request the same extensions of time for the divisional application as were requested for the parent application. This is to allow sufficient time for the divisional application to be prosecuted.

If a divisional application is filed within the last six months of the rule 30 period of the parent application, all correspondence to the UKIPO should be marked as “URGENT”. Further, if the claimed invention incorporates subject matter that was not previously claimed from the description, then basis for the newly claimed matter should be clearly identified to avoid delays.


The change in practice will significantly impact the timing and compliance requirements for filing and prosecuting divisional applications to grant. Therefore, applicants should carefully consider the impact of this modified practice on the time available to them to file and prosecute divisional applications.

Applicants should also carefully consider the timing of filing divisional applications and the requirement to extend the compliance period of the divisional application.

In summary, D is for Divisional Applications with reduced compliance periods, so applicants should not delay and file early to avoid potential time constraints.

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