Cintec International Ltd v John Humphries Parkes (t/a Dell Explosives) & Anor

Under Patents Act 1977, a threat exists where a communication would convey to a reasonable recipient that patent infringement proceedings will be brought against a person or product. Express threatening words are unnecessary, and the court assesses the communication in its full context. A threat may be made to a third party. The statutory exclusion for threats concerning manufacture, importation or use is narrow and does not protect threats concerning sales. The scope of a threat is a question of fact, including which patents it covers. For infringement, the claims define the monopoly. The court must construe the claims and apply the Protocol on Interpretation; it cannot enlarge the monopoly by reference to the supposed equity of a patent or the prosecution history.

Cintec developed water-filled blast-mitigation products. The defendants, who held patents concerning water suppression of explosions, sent communications to Cintec and third parties alleging infringement and threatening legal action. Cintec brought proceedings under section 70 of the Patents Act 1977. The defendants relied on justification and counterclaimed for infringement of four United Kingdom patents.

The principal issues were whether the communications amounted to actionable threats and whether Cintec’s products infringed the pleaded patent claims.

1. Threats. The court applied the reasonable-recipient test. The letter to Cintec was an actionable threat concerning all nine patents identified by the defendants, including patents which they admitted were not infringed. It was not protected by without-prejudice privilege because it was a demand for payment and a licence under threat of immediate proceedings, rather than part of genuine negotiations.
2. The letter to Transco was also a clear threat of patent infringement proceedings directed at Transco in relation to Cintec’s products. The communication’s title, references to disputed intellectual property and references to litigation in the United Kingdom and the United States conveyed that meaning. The defendants’ assertion that the letter communicated only product-safety concerns was rejected.
3. The conversation with Qinetiq gave rise to an actionable threat insofar as the defendants’ earlier communication threatened to sue Cintec. The later disclosure that Scottish infringement proceedings had commenced was not itself actionable because there was no threat to expand the litigation.
4. The exclusion in section 70(4) was inapplicable. The threats included Cintec’s sales activities, so section 70(3) could not provide a defence. Threats concerning patents admitted not to be infringed were unjustified.
5. Infringement. The ‘750 claims required lay-flat plastic tubing and, in relevant claims, separated liquid volumes in series. Cintec’s products used materially different dropstitch fabric and did not satisfy those requirements.
6. The ‘259 and ‘614 claims required rigid barriers or rigid blocks distinct from rupturable liquid-filled bags. Water-filled bags, even when taut or pressurised, were not rigid barriers or blocks. The ‘805 claim required a separate free-standing, collapsible, rigid frame and a rupturable container. Cintec’s products contained no such frame. The infringement allegations therefore failed.
7. The court treated prosecution history as valueless and without weight in the absence of file-wrapper estoppel. Cintec succeeded on its threats claim and the defendants failed on their counterclaim.