Kohler Mira Limited v Norcros Group (Holdings) Limited

The patent claims are invalid for insufficiency due to uncertainty; the specification does not provide a criterion for 'substantially unchanged' flow rate, making the boundary of the claim impossible to determine. Triton's products do not infringe as the result is achieved by other components, not the diverter valve, and the risk of scalding criterion is not the applicable test.

Parties: Claimant/respondent: Kohler Mira Limited; Defendant/appellant: Norcros Group (Holdings) Limited
Jurisdiction: England and Wales
Judgment Date: 01 September 2026
Procedural Posture: Civil Appeal / Court of Appeal Judgment
Outcome: Appeal allowed; patent revoked for insufficiency; no infringement found.
Legal Topics: Patent Infringement, Patent Validity, Claim Construction, Insufficiency, Uncertainty

Intellectual Property Patent Law Patent Infringement Patent Validity Claim Construction Insufficiency Uncertainty

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Parties

Kohler Mira Limited

Claimant/respondent

Norcros Group (Holdings) Limited

Defendant/appellant

Procedural Posture

Civil Appeal / Court of Appeal Judgment

Legal Issues

1 Interpretation of claim 1 of UK Patent No. 2466504
2 Whether Triton's DuElec range infringes claims 1 and 4
3 Whether claims are invalid for uncertainty

Ratio Decidendi

Court Disposition

Appeal allowed; patent revoked for insufficiency; no infringement found.

Orders

Patent revoked for insufficiency under section 72(1)(c) of the Patents Act 1977.
Declaration that Triton's DuElec range does not infringe claims 1 or 4 of UK Patent No. 2466504.