Regulation 25

Without prejudice to the generality of section 25 (5) (d), where 2 or more inventions are claimed (whether in separate claims or as alternatives within a single claim), such inventions shall be treated as being so linked as to form a single inventive concept only when there is a technical relationship among those inventions involving one or more of the same or corresponding special technical features.

In this rule, “special technical features” means those technical features which define a contribution which each of the claimed inventions, considered as a whole, makes over the prior art.