Unregistered design right cannot be applied to design features of an article if the appearance of those features is dependant on that of a larger article of which it is intended to form an integral part. For example there could be no unregistered design right in spare parts for cars or prostheses for people with artificial limbs.
The case of Dyson Limited v Qualtex (UK) Limited is a good example of this. Dyson was seeking to prevent the sale of spare parts made by Qualtex to fit and match Dyson vacuum cleaners. The Qualtex parts in question were intended to resemble closely the Dyson spares, not least as they were visible in the normal use of the vacuum cleaners. It was held that the must match exclusion will not apply if the design of the spare part could be itself changed without radically changing the overall appearance of the whole article i.e. the vacuum cleaner. In other words, it was not necessary for Qualtex spares to be identical in appearance to the Dyson ones, so the exclusion did not save Qualtex from infringement of Dyson’s unregistered design right.
The Court of Appeal broadly upheld the judge’s approach and confirmed that it was for the spare parts dealer or manufacturer to show that, as a practical matter, there was a real need to copy some feature of shape or configuration ( because the appearance on the entire article was dependent upon the relevant design feature of the spare part). If there was no such dependence the consequence would be that any unregistered design right subsisting in that feature of the original design and article could properly be protected and would not be excluded by ‘must match’ and the spare part would constitute an infringing article.