UK Shower Patent Dispute

1. Background

Shower manufacturer, Mira is the owner of UK Patent No.GB 2,466,504 (Patent), which was granted on 10 July 2013 (the filing date and priority date is 24 December 2008). The Patent relates to an electric shower, which has two or more outlets.

Electric showers available on the market at the priority date were limited to only one outlet because of the risk of scalding if the water flow was significantly impaired during operation. Mira’s Patent offered a solution to the issue.

Mira claimed infringement of the Patent by Triton’s ‘DuElec’ range of electric showers, which are marketed in the UK and have two outlets – an overhead shower and a hand shower. Deeley was the key piece of prior art cited by Triton in its validity attack on the Patent.

Both Mira and Triton are UK registered companies, which are well-known and long-established shower manufacturers.

2. Decision

The Court had to decide on the below.

Validity

Was the patent:

• Novel over UK Patent Application No 2,274,985A (Deeley)?
• Inventive over i) Deeley in conjunction with the common general knowledge; and ii) the common general knowledge?
• Invalid for lack of sufficiency?

Infringement

Did Triton’s DuElec Range infringe the Patent?

The Court found that the Patent was novel over Deeley, inventive and sufficient. Therefore, it was held to be valid.

Regarding infringement, the Court also found that Triton’s DuElec showers fell with the scope of claims 1 and 4 of the Patent and so infringed it. 

3. Expert witness: key learnings

Each party instructed their own expert witness.

• Expert evidence should be independent

In his expert report, Triton’s expert stated that Deeley had two “distinct concepts”, namely i) a shower unit with multiple outlets and a diverter valve, and ii) a control unit for such installations. However, when he was cross-examined, the expert could not recall the two concepts he had described.

Mira’s solicitors criticised Triton’s expert evidence, suggesting that this could be because this wasn’t his own opinion but Triton’s solicitor’s opinion.

Whilst the judge said there was no evidence to suggest this, she did say that the fact Triton’s expert could not recall the two concepts undermined his evidence.

• Experts should not engage in the role of advocates

Mira’s expert filed a report stating that there were no dual-outlet electric showers on the market in the UK at the priority date.

Triton’s expert did not acknowledge this fact in either of his expert reports. The judge found this to be a “surprising omission”. Instead, he stated that there were certain “commercial barriers” to selling dual-outlet electric showers in the UK. In cross-examination, Mira’ s counsel accused him of seeking to make excuses for the fact that there were no electric showers on the priority date without acknowledging this fact.

This aspect of the evidence was one of the reasons, which caused the judge to “generally prefer the evidence” of Mira’s expert.

It is vital that experts remain independent and do not attempt to use their evidence to argue a party’s case.

• Experts and how they are provided key documents in patent infringement cases

This final point concerns instructing solicitors and how they provide key documents to experts in patent infringement cases. However, it is useful for experts to be aware of this, to minimise their evidence being openly criticised for bias.

The parties took different approaches to the provision of documents to their experts:

• Mira’s solicitors followed a process called sequential unmasking. This has been considered in previous cases as the correct approach to instructing experts in patent infringement cases. The concern being that if an expert is shown the patent before they have assessed what the common general knowledge is or said what they consider to be obvious over the prior art, there is a risk of hindsight creeping into their assessment. In following this process, Mira’ s solicitors asked Mira’s expert to describe the common general knowledge in relation to showers at the priority date. The expert was then provided with Deeley and found and read McMaster-Christie himself. After discussing both with Mira’s solicitors, he was then provided with the Patent and other key documents.
• Triton’s expert was told by Triton’s solicitors from the outset that Triton was attacking the validity of the Patent. He was provided with both Deeley and McMaster-Christie, as well as the Patent and key documents including the pleadings.

In relation to the approach taken by Mira’s expert, the judge stated, “this is, in my judgment, the proper way for an expert to go about his task”.

4. Best practice

This case highlights how impactful an expert’s conduct and their compliance with the relevant rules can be on how the court views their evidence.

The judge described Mira’s expert as a “very good witness, careful, credible and reliable”. Whereas she expressed concern over Triton’s expert – specifically, his “approach to his task as expert, his confusion over the proper approach to what prior art was and was not in the common general knowledge [and] the number of assertions he made which he was forced to resile from as incorrect.” 

This led to her “generally” preferring the evidence of Mira’s expert and ultimately their success in the case.

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