Threats of patent infringement
Threats of patent infringement

The following IP guidance note provides comprehensive and up to date legal information covering:

  • Threats of patent infringement
  • Introduction
  • Reform of the unjustified threats regime
  • Transitional provisions
  • Application of the Rules
  • What is a threat?
  • What is an actionable threat?
  • Permitted communication
  • Remedies and defences
  • The Unitary patent and Unified patent court
  • more


Patent litigation is recognised as being time consuming and often costly. The statutory threats provisions attempt to minimise the disruption to businesses that are threatened by rights owners wielding their registered 'monopoly' rights in an overly aggressive and unjustified way. Anyone writing or sending a letter or other communication alleging, or even implying, patent infringement in the UK should be aware of the risk of becoming a defendant in an unjustified threats action.

Under the Civil Procedure Rules 1998, Practice Direction — Pre-Action Conduct and Protocols, a potential claimant is required to set out its case sufficiently to allow the potential defendant to assess the claims made against it. Without sufficient care, sending pre-action correspondence to satisfy these pre-action requirements may mean that actionable threats are made. This requirement is sometimes deliberately not met because of the threats provisions.Practice Direction Pre-Action Conduct and Protocols

The tactical importance of a threats action is that it gives an alleged infringer the opportunity to take the initiative in the proceedings and puts the entity that would have been the claimant in an action on the receiving end of a claim as a defendant and therefore not in control of the litigation timetable.

Reform of the unjustified threats regime

The unjustified threats regime as it relates to patents is governed by the Patents Act 1977 (PA 1977). However, significant reforms were introduced by the Intellectual Property (Unjustified Threats) Act 2017 (IP(UT)A 2017), which substantially amended and expanded these provisions. IP(UT)A 2017, ss 7–9 came into force on 27 April 2017 and the substantive parts were implemented by Statutory Instrument on 1 October