Welcome to the new version of the Patents Manual. Please note there are changes to the numbering and sequence of the chapters and pages in the manual. You are encouraged to take the time to explore and familiarise yourself with this new structure. Claims directed to a single invention (Unity)

Date Published

Key Legislation:

Patents Act:

  • s40 claims must relate to one invention only

Regulations under the PCT:

PCT ISPE Guidelines:

PCT Administrative Instructions:

Related Chapters:

Examination Practice

Section 40(4) of the Patents Act 1990 states:

"The claim or claims must relate to one invention only."

In general, the procedure followed to determine whether there is more than one invention claimed is the same as for ‘lack of unity’ under Rule 13 of the PCT Regulations.

​​​​​​​Examiners are therefore to have regard to the following references, which contain a comprehensive guidance on assessing unity of invention:

Restricting examination

In National examination if Lack of Unity has been determined, no additional examination fees are requested. Instead, examiners are expected to restrict search and examination to the first claimed invention only. The applicant should be informed that opinion on any other inventions is reserved.  

Exceptions to this general approach can occur when there is negligible additional effort required for examining the additional inventions, or the FERs indicate preference for later inventions. Further guidance on these circumstances is outlined in 3.3.4 Reserving Opinion and Restricting Search​​​​​​​.

If the claimed inventions are clearly not linked to form a single inventive concept, then a lack of unity objection should be raised regardless of whether or not additional inventions are examined due to negligible effort.

Restriction (in part)

Where a claim encompasses embodiments directed to more than one invention and opinion has been restricted, the lack of unity objection should indicate that part of the claim concerned has been examined, while part has been reserved.  

For example:

Claim 21 encompasses a compound that contains formula 1 and formula 2. Formula 1 is the unique feature of Invention 1, while Formula 2 is the unique feature of invention 2. The lack of unity objection should identify claim 21 as partially belonging to both groups of inventions.

Invention 1. Claims 1-20 and 21 (in part) relate to compounds of formula 1, a process for their preparation, pharmaceutical compositions containing them and methods for their use as antibiotics.

Invention 2. Claims 21 (in part) and 22-29 relate to compounds of formula 2, pharmaceutical compositions containing them and methods for their use as anti-inflammatories.

I have limited the search and report to Invention 1 as defined by Claims 1-20, 21 (in part).

When I receive a response to my objections, I may extend the search area and expand the report on the basis of my findings.

Relevant citations for other inventions

If a search locates prior art relevant to some of the other claimed inventions for which a search has not been conducted, examiners should raise an objection to the effect that while a search has not been conducted with respect to certain claimed inventions, those claims are anticipated by the prior art.

Amended Reasons

Amended Reason Date Amended

Published for testing

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