Interlocutory Practice in the UK

Interlocutory actions in the UK Courts are available to a claimant who needs a rapid temporary injunction to be in place pending full trial. Typically, in cases involving a patent, these actions are sought when a patentee believes that a patent has just been or is about to be infringed by entry of a new product onto the market.

When considering the request for an interlocutory injunction, the Courts are reluctant to consider technical matters concerning the alleged infringement of the patent or the Patents alleged invalidity in detail. In particular the Court is reluctant to consider issues where expert evidence is required.

From this it follows that the patentee has to make only an arguable case on infringement, i.e. put forward only a prima facia case that requires expert evidence to rebut.

There is no requirement to show that the case is likely to succeed at full trial; all that is required is that it is sufficiently credible to require response.

Similarly, invalidity can only be relied upon by the defendant in extremely clear circumstances, for example where there is novelty destroying prior art the relevance of which is not properly challenged by the patentee.

If it requires expert evidence to characterise the prior art it is unlikely to be effective during interlocutory procedures.

Since technical issues do not play a major role in interlocutory proceedings the issue is settled on the “balance of convenience” to the parties.

The decision concerning balance of convenience is based on commercial matters. Both parties seek to show that they will suffer harm which cannot be repaired by the simple award of damages at full trial if they are successful.

This is often on the basis of the unquantifiable nature of the damage, for example loss of reputation, unrecoverable market share, market devaluation and the like.

Generally both parties will be required to provide a cross undertaking in damages. The Court will balance the cases put forward by the two parties and decide whether an injunction pending full trial should be given.

It is not unusual for such decisions to favour the status quo and preserve the position as it is at the date of interlocutory decision.

Thus for example in the case of an action brought to prevent entry of a product into the market, the decision may well be to prevent entry of that product until full trial.

If the patentee’s arguments for irreparable damages relate to loss of an exclusive position, then if it is shown that such an exclusive position will be lost in any event through actions of a third party entering the market, then the Court is less likely to find in the patentees favour.

An example of this is where a basic patent on a pharmaceutical product is due to expire and the patentee has another patent on formulations of that product that is alleged to be infringed by the defendant.

If several generic pharmaceutical manufactures seek to enter the market at the same time with a number of products, but not all are sought to be restrained, then it is unlikely the Court will be persuaded to grant an injunction.

The Court is likely to take into consideration actions of the defendant to “clear the way” for introducing his product, for example to revoke the patent or to demonstrate to the patentee that there is no infringement.

This later may involve supplying the patentee with an example of the product sufficiently far before hand so that an interlocutory action becomes unnecessary. Such actions will enhance the defendant’s position.

The Court may well be prepared to set an early date, for example in 3 to 4 months, for the full trial if an action for interlocutory injunction is undertaken.

The information provided in this article is, of course, of a general nature and should not be considered as legal advice; if you have any specific questions, please contact Jon Broughtonat HLBBshaw in Epping, Essex, UK. E-mail: Visit the website at

The information contained in this alert is provided for informational purposes only and does not represent legal advice. Neither the APLF nor the author intends to create an attorney client relationship by providing this information to you through this message.


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