Factual and Procedural Background
The patent appeal arises from infringement proceedings initiated by Company A against Company B (now renamed Company C) concerning European Patent (UK) No 1 435 338 ("the patent"). Company B denied infringement and counterclaimed for revocation of the patent on grounds including lack of novelty, obviousness, and insufficiency. The lack of novelty objection was abandoned, and the trial judge rejected the objections of obviousness and insufficiency, finding the patent valid and infringed. Company B appeals only the rejection of the insufficiency ground.
Two further procedural appeals concern whether Company D, the parent company of Company C, can be joined as a defendant to be held responsible for damages awarded against Company C. Company A alleges that Company D was a joint tortfeasor with Company C during the period it was the parent company ("the Company D period") and that Company D acquired liabilities of Company E, a previous parent company of Company C ("the Company E period"). Company D did not appear or contest certain findings below, but disputes the wider joint tortfeasor liability and the transfer of liabilities from Company E to Company D.
The procedural history includes judgments from Deputy High Court Judges addressing these joinder and liability issues, with appeals arising from those decisions.
Legal Issues Presented
- Whether the patent claim language "consisting essentially of" causes objectionable uncertainty rendering the patent invalid.
- Whether the patent claim insufficiently describes the invention, thus invalidating the claim.
- Whether Company D can be joined as a defendant on the basis of joint tortfeasor liability with Company C during the Company D and Company E periods.
- Whether liabilities of Company E transferred to Company D.
- The scope of proceedings against Company D, specifically whether liability extends beyond certain seized goods.
Arguments of the Parties
Appellant's Arguments
- The phrase "consisting essentially of" creates uncertainty because determining infringement requires a materiality test comparing the alleged infringing product to a comparator without the added ingredient, which is practically impossible due to process secrecy and product composition.
- The claim is overly broad, covering all products with desirable characteristics regardless of whether they are made by the patentee's method or owe anything to the patentee's contribution, thus insufficiently describing the invention.
- Company D should not be held liable as a joint tortfeasor beyond the specific acts relating to the seized goods, and it is not arguable that Company E incurred joint tortfeasor liability or transferred it to Company D.
Appellee's Arguments
- The skilled person understands "consisting essentially of" to exclude ingredients materially affecting essential characteristics, thus no objectionable uncertainty arises.
- The patent claim breadth is justified because all covered products are unified by a common principle and enabled by the specification and common general knowledge.
- Company D is arguably jointly liable with Company C for acts during the Company D period and has assumed liabilities of Company E, justifying joinder and extension of proceedings.
- The scope of the common design between Company D and Company C is at least arguable to extend beyond the seized goods, allowing a broader inquiry.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Virgin Atlantic v Premium Aircraft [2009] EWCA Civ 1062 |
Interpretation of "consisting essentially of" in patent claims as excluding ingredients materially affecting essential characteristics. |
Supported the construction that the phrase creates a penumbra around the core ingredient excluding materially affecting additions; no appeal against this interpretation. |
| Kirin Amgen and others v Hoechst Marion Roussel Ltd [2004] UKHL 46 |
Insufficiency arising from conceptual uncertainty where the skilled person cannot determine the scope of the claim due to unclear test criteria. |
Used to distinguish between fuzzy boundaries and conceptual uncertainty; the court found no such conceptual uncertainty here. |
| Milliken Denmark AS v Walk-Off Mats Limited [1996] FSR 292 |
Illustration of conceptual uncertainty (e.g., non-existent measurement units) leading to insufficiency. |
Used as an example to explain the difference between ambiguity and uncertainty in patent claims. |
| Generics (UK) Ltd v H. Lundbeck A/S [2009] UKHL 1 |
Burden of proving insufficiency and that broad claims must be enabled across their full scope. |
Confirmed that a broad claim is not invalid merely for breadth; insufficiency must be established on evidence. |
| Biogen Inc v Medeva plc [1997] RPC 1 |
Claims must not extend to embodiments that owe nothing to the patentee's technical contribution. |
Applied to assess whether the claim covers products not enabled by the patent or outside the patentee's contribution. |
| Regeneron Pharmaceuticals Inc v Kymab Ltd [2018] EWCA Civ 671 |
Claims to products/components of the future may be valid if enabled by a disclosed principle. |
Referenced as an example of claims covering future components enabled by the invention's principle. |
| Electrical & Musical Industries v Lissen Ltd (1939) 56 RPC 23 |
Claims define the boundary of the monopoly to inform others of the limits of the patent right. |
Emphasized the importance of clear boundaries for patent claims; supported the "fuzzy boundary" concept. |
| Sandvik Intellectual Property Ltd v Kennametal UK Ltd [2011] EWHC 3311 (Pat) |
Distinguishing fuzzy boundaries from true ambiguity causing insufficiency. |
Supported the conclusion that unclear test criteria causing uncertainty lead to insufficiency. |
| Generics UK Ltd v Yeda Research and Development Co Ltd [2012] EWHC 1848 (Pat) |
Clarification that difficult-to-interpret claims with fuzzy boundaries are not necessarily insufficient, but true ambiguity is. |
Approved by the court as a guide to distinguishing uncertainty from ambiguity. |
| MCA Records Inc v Charly Records Ltd [2001] EWCA Civ 1441 |
Principles governing joint tortfeasor liability of directors and controlling shareholders. |
Applied to assess whether parent companies exceeded constitutional control to incur joint tortfeasor liability. |
| Standard Chartered Bank v Pakistan National Shipping Corporation (No 2) [2000] 1 Lloyd's Rep 218 |
Limitations on director liability for acts within constitutional governance roles. |
Referenced in context of liability of officers of parent companies. |
Court's Reasoning and Analysis
The court first addressed the patent appeal concerning the phrase "consisting essentially of" and the sufficiency of the patent claim.
The court accepted the trial judge's construction that "consisting essentially of" excludes ingredients materially affecting the essential characteristics of the product, thus creating a penumbra rather than a strict boundary. This interpretation aligns with established patent practice and relevant case law.
The first insufficiency attack—that the phrase causes uncertainty requiring impossible testing to determine infringement—was rejected. The court held that the test for sufficiency is whether the specification enables a skilled person to perform the invention, not whether a purchaser without relevant skill can determine infringement. The alleged need for a comparator sample without the added ingredient was deemed unrealistic and not a proper basis for insufficiency.
The court distinguished between fuzzy boundaries at the edge of claims, which are acceptable, and conceptual uncertainty rendering a claim insufficient, as illustrated in Kirin Amgen. The present case involved only a fuzzy boundary, not conceptual uncertainty.
The second insufficiency attack challenged the breadth of claim 1, alleging it covered products not enabled by the patentee's contribution. The court reviewed the principles from Biogen and Lundbeck, emphasizing that claims must not extend to embodiments owing nothing to the patentee's technical contribution.
Applying these principles, the court found that the patent enabled a wide range of products within the claim and that Company B failed to prove the existence of products covered by the claim but not enabled by the specification. The evidence showed only that different manufacturing methods might affect product morphology, but not that such products were outside the patent's enablement.
Accordingly, both insufficiency attacks failed.
Regarding the procedural appeals, the court analyzed whether Company D could be joined as a defendant on joint tortfeasor grounds.
The court found a triable issue that Company D was jointly liable with Company C during the Company D period, based on active involvement in infringing acts related to seized goods and executive control beyond constitutional governance. This justified joinder for that period.
Conversely, the court held that Company A had not shown a triable issue that Company E was jointly liable with Company C during the Company E period, as mere corporate control was insufficient without evidence of involvement in wrongful acts.
However, the court found it arguable that Company D acquired liabilities of Company E pursuant to a court-approved scheme of arrangement, allowing the claim to proceed for the Company E period.
On the scope of proceedings against Company D, the court rejected the argument that liability should be limited to the seized goods. It held that if a common design to infringe existed beyond those goods, the inquiry could extend accordingly. The Practice Direction requiring at least one example of each infringement type does not limit the scope of joint tortfeasor liability once established.
Holding and Implications
The court DISMISSED the patent appeal, upholding the validity of the patent claims against the insufficiency challenges.
The court ALLOWED the procedural appeals, permitting Company D to be joined as a defendant on joint tortfeasor grounds for both the Company D and Company E periods, including the assumption of liabilities from Company E.
The implications are that Company D may be held liable for damages alongside Company C for infringing acts during the relevant periods. The court did not set new precedent but applied established principles to the facts, emphasizing the importance of distinguishing between fuzzy claim boundaries and conceptual uncertainty, and clarifying the standards for joint tortfeasor liability in corporate group contexts.