Difficulties of proving innocence to patent infringement

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Section 62(1) of the Patents Act 1977 provides that in proceedings for infringement of a patent, damages shall not be awarded nor an account of profits ordered against a defendant who is able to show that, at the date of the infringement, he was not aware, and had no reasonable grounds for supposing, that that patent existed. This defence of “innocent infringement” is in practice rarely relied upon, probably because it is difficult to prove – and it is for the party seeking to rely on it to prove it. The recent High Court case of Collingwood Lighting Ltd v Aurora [1] is a reminder of how difficult it can be.

In this case, Collingwood sued Aurora for infringement of its patent for a fire-resistant LED downlighter unit. Aurora maintained that the patent was invalid for lack of novelty. If, however, the court should uphold the patent, Aurora relied on the innocent infringement defence to Collingwood’s damages claim.


The High Court upheld the patent, finding it novel and non-obvious. The court then turned to the question of infringement, specifically the defence put forward by Aurora of innocent infringement.

The court reminded itself that the question of whether a defendant had “reasonable grounds” for supposing that a patent existed was an objective test. Further, if the defendant should have known that the patent existed, it was immaterial that the defendant considered that the patent was invalid or that its product would not infringe.

The only witness called by Aurora said that he was personally unaware of Collingwood’s patent at the time the infringing design was produced. However, that did not mean that others at Aurora were not unaware of it. In particular, the witness admitted at trial that Aurora technical and sales staff would have read a trade magazine detailing the Collingwood product before Aurora began design of their own product. The article in the magazine, and accompanying advertisement did not refer to a patent at all, but it was common practice in the sector for “innovative” (which is how the design was described in the magazine) designs to be patented. Aurora would have been put on notice therefore that the Collingwood product might be patent protected.

The court held that Aurora had failed to discharge its burden of showing that no reasonable grounds for supposing that a patent existed.


[1] [2014] EWHC 228 (Pat)