Dyson Appliances Limited -v- Hoover Limited (No. 2)

United Kingdom
Patents Court (R.M. FYSH QC), 11th January 2001


In a recent landmark decision, the Patents Court has held that injunctions may be granted for a specified period after the date of expiry of a patent as an alternative to damages for this same period, the latter allowed following the ruling in Gerber -v- Lectra. Such post-expiry injunctions may be awarded where just and convenient to prevent a defendant from benefiting from its infringing activities during the term of the patent to the detriment of the patentee and, in particular, to prevent the defendant obtaining a "springboard" into the relevant market. This is the first decision to consider this aspect of post-expiry relief in patent infringement actions for some considerable period of time, although post-expiry injunctions have been granted to successful patentees in other jurisdictions. On the facts, the Court granted a limited injunction in respect of the specific infringing product considered at trial, for a period of 12 months from the date of expiry of the patent. The Court considered the further injunction sought, relating to the Defendant's trade marks for the infringing product, to be neither just nor convenient.


On 3rd October 2000, the Patents Court held that Dyson's European Patent (UK) no. 0042723 ("the Patent") had been infringed by the manufacture and sale of Hoover's Triple Vortex vacuum cleaner. The Court dismissed Hoover's counter-claim to revoke the Patent.

At a subsequent hearing to determine the form of order to be made, Dyson sought the following additional novel injunctive relief:

  • Post-patent-expiry injunctions for a specified period (12 months) to prevent Hoover selling its Hoover Triple Vortex vacuum cleaner or any other vacuum cleaner made in accordance with the invention as claimed in the Patent ("the Post-Expiry Injunctions").

  • An immediate trade mark injunction for 6 months to prevent Hoover marketing any vacuum cleaner under the VORTEX trade marks ("the Trade Mark Injunction").

The relevant factual background established by the Court was that it would take the Defendant at least 12 months to develop a product incorporating the essential features of the claims of the Patent, noted to have particular technical benefits, and that, as a result of its infringing activities during the term of the Patent, it would be able to recommence sales of the infringing product very quickly upon patent expiry, although a certain lead-in time would be required. The Court also noted that the Defendant had a policy of continuous product development and that their past experience with the infringing product might hasten their entry into the market with other new models, although found that there was no evidence directly on this point. Hoover had also generated some valuable goodwill in the VORTEX trade marks.


  • Whether the Post-Expiry Injunctions should be granted; and

  • Whether the Trade Mark Injunction should be granted.


Although the Court noted that it might seem anomalous with the underlying purpose of the patent system, the Court was persuaded that it had power to grant post-patent-expiry injunctive relief in lieu of post-patent-expiry damages, particularly when such damages were difficult to assess accurately. In particular the Court held that by virtue of Section 37 of the Supreme Court Act 1981 and its inherent equitable jurisdiction, it could make Post-Expiry Injunctions of the kind sought by the Claimant where it was just and convenient to do so. The Court distinguished the facts of the case from the three authorities cited by Hoover and noted the distinction between the prevention of infringing activities during the post-expiry period and prevention of an infringer benefiting in the post-expiry period from infringing activities committed pre-expiry.

The Court held that, in addition to the principal substantive infringing activities of sale and manufacture of the infringing products complained of in the action by Dyson, the "in-house activities" of making prototypes, and using and testing those prototypes, and submitting samples of the finished appliances to the regulatory authorities for testing and approval were all additional infringing acts. Further, a person wishing to exploit an invention relating to a product after the patent had expired must wait until expiry before undertaking any practical steps to this end, save perhaps on paper. Hoover's in-house development of the infringing product up to the marketing stage and prior to the expiry of the Patent involved infringing activity and, to have been legitimate, should have awaited the expiry of the Patent. On this basis, the Court found that Dyson would have been likely to have been entitled to secondary damages in accordance with the principle in Gerber -v- Lectra.

In light of the difficulty of calculating such secondary damages, the injunction sought, relating to sale of the infringing product in question for a period of 12 months after expiry of the patent, was both just and convenient. The injunction was, however, to be limited to the particular product in question, along the lines suggested by Laddie, J in Coflexip SA -v- Stolt Comex and not to the wider form of injunction also sought, covering any product falling within the claims of the Patent - such latter form of injunction being neither convenient nor necessary. In so limiting the injunction, the Court was particularly influenced by the fact that there was no evidence that the Defendant would produce anything other than the infringing product post-patent-expiry and by the likely inconvenience that would be caused in any potential contempt proceedings, in the need to consider infringement.

As concerns the Trade Mark Injunction sought, the Court noted that the injunction had been framed broadly and in a way which made it inconvenient to grant the relief sought. Further there was little evidence to support the breadth of such injunction and it was not clear that loss would flow from use of the VORTEX trade marks as a foreseeable consequence of the patent infringement. Accordingly the Court found the Trade Mark Injunction to be neither just nor convenient and certainly not necessary.


The Judgment in this case represents a highly practical decision by the Patents Court, in particular recognising the difficulty of accurately assessing damages for "springboard relief" according to the principles in Gerber -v- Lectra. The decision is likely to have a very significant impact in patent litigation, particularly where the patent in suit is nearing expiry and where the lead-in time in the relevant industry is relatively long. The claimant now has a choice in such circumstances between claiming post-expiry damages under Gerber -v- Lectra and post-expiry injunctive relief pursuant to this case. Further, although on the facts the Trade Mark Injunction was not allowed, the way has been left open for patentees in future cases to argue this point again.

For further information, please contact Stephen Whybrow by e-mail at stephen.whybrow@cms-cmck.com or by telephone on +44 (0)20 7367 2175.