I have just updated and transposed two articles that appeared on the old Kingsgate Chambers and Lancaster Buildings websites on threats actions.
The first of these used to be the home page for the "threats" section on the old Kingsgate website. The updates are the changes made to s.70 of the Patents Act 1977 by s.12 of the Patents Act 2004 and the creation of a threats action in respect of Community designs by reg. 2 of The Community Design Regulations 2005.
The other article is "Actionable Threats in Intellectual Property Litigation". I wrote the first edition on Prince Charles's 51st birthday (14 Nov 1999) which was after the Court of Appeal had given judgment in Unilever Plc v Proctor and Gamble Co  FSR 433 but before Mr Justice Pumfrey had decided Kooltrade Ltd. v XTS Ltd.  FSR 344. Indeed, I actually predicted the result of the main point of argument in Kooltrade, namely that the "without prejudice" privilege applies only to genuine attempts to settle litigation and is not a lucky charm. I never thought that I would be the one to make that argument 6 months later.
Also on the site is one half of a PowerPoint presentation that my friend, Susan Hall of Cobbetts LLP and I gave to the Northern Circuit Commercial Bar Association at the Midland Hotel, Manchester on 5 March 2002 entitled "Threats Actions: A Trap for the Unwary" together with my handout. As I have already indicated above, the law has changed a bit since 2002 so be careful how you choose it. Check the other articles or, better still, check with me on +44 (0)870 990 5081. I remember that Susan and I had a very good house despite the fact that David Berkeley QC, who was then Vice-Chair of the Association, chose that night for some kind of hospitality event for Merchant Chambers. We still managed to attract many of the solicitors in Manchester who know about IP, including Jonathan Moakes and Colin Hoffmann.
The other item on threats is an article I did last June for my colleague Toni Tease in the USA entitled "Consider the Implications of Foreign Laws Before Sending a Cease and Desist Letter". It is intended for US lawyers but non-IP litigators from the UK would also do well to read it. One of the few areas of the law where I probably have more experience than most of the London patent bar is threats actions and that is because most of my professional access clients are small suburban or country solicitors. Not that there is anything wrong with them I might add. Some of them could give much bigger Manchester and Leeds firms a run for their money and one such firm in Carnforth regularly sees them off. The reason that article appears on a US website is that the American courts award triple damages for wilful infringement but you have to put the defendant on notice that he is infringing your patent in order to claim such damages.