Trademark Dilution, Trademark Infringement
Passing off has developed from the common law. The basic difference between an infringement action and an action for passing off is that an infringement action is a statutory remedy and an action for passing off is a common law remedy. Passing off and trademarks law deal with overlapping factual situations. Passing off does not confer monopoly rights. To establish infringement with regard to a registered trademark, it is necessary only to establish that the infringing mark is identical or deceptively similar to the registered mark and no further proof is required. Whereas in the case of a passing off action, proving that the marks are identical or deceptively similar alone is not sufficient, there should be proof that the use of the mark is likely to deceive or cause confusion. In a passing off action it is also necessary to prove that the use of the trademark by the defendant is likely to cause injury or damage to the plaintiffs goodwill.
Fundamental elements to passing off
The three fundamental elements to passing off are therefore reputation, misrepresentation, and damage to goodwill, which are sometimes known as the classical trinity, as restated by the English House of Lords in the case of Reckitt & Colman Ltd v Borden Inc  1 RPC1 341 1 (the Jif Lemon case). Lord Oliver stated the matters which a successful plaintiff must establish, as follows:
He must establish a goodwill or reputation
attached to the goods or services.
He must demonstrate a misrepresentation by the defendant to the public (whether intentional) leading or likely to lead the public to believe that the goods or services offered by him are goods or services of the plaintiff.
He must demonstrate that he suffers 'loss or damage as a consequence of the erroneous belief that the goods or services of the defendant are the goods or services of the plaintiff'.
Passing off does not recognize them as property in its own right, but prevents one person from misrepresenting his or her goods or services as being the goods and services of another person or the plaintiff in infringement proceedings. The law of passing off is designed to prevent misrepresentation to the public where there is some sort of association between the plaintiff and the defendant.
Misrepresentations include: using the mark of the
plaintiff's product, using the get-up of the plaintiff's product, using the plaintiff's
advertising theme and using the design or shape of the plaintiff's product.
Passing off occurs when a person holds out his or her goods or services as having some association or connection with the plaintiff when this is not factually true.
The plaintiff can initiate action against the defendant in a situation where the defendant does something so that the public is misled into thinking the activity is associated with the plaintiff, and as a result the plaintiff suffers some damage.
Passing off is a common law tort which can be used to enforce unregistered trademark rights. Statutory law such as the United Kingdom Trade Marks Act 1994 provides for enforcement of registered trademarks through infringement proceedings.
A cause of action for passing off is a form of intellectual property enforcement against the unauthorised use of a mark which is considered to be similar to another party's registered or unregistered trademarks, particularly where an action for trademark infringement based on a registered trade mark is unlikely to be successful because of the differences between the registered trademark and the unregistered mark.
Extended passing off
One of the instances where passing off is actionable is the extended form of passing off, where a defendant's misrepresentation as to the particular quality of a product or services causes harm to the plaintiff's goodwill. Erven Warnink v J Townsend & Sons (Hull) Ltd  AC 731, in which the makers of advocaat sued a manufacturer of a drink similar but not identical to advocaat, but which was successfully marketed as being advocaat.
The extended form of passing off is used by celebrities as a means of enforcing their personality rights in common law jurisdictions. Common law jurisdictions do not recognise personality rights as rights of property. Accordingly, celebrities whose images or names have been used can successfully sue if there is a representation that a product or service is being endorsed or sponsored by the celebrity or that the use of the likeness of the celebrity was authorised when this is not true.
Reverse passing off
Reverse passing off occurs where the defendant markets the plaintiff's product as being the defendant's product (see John Roberts Powers School v Tessensohn  FSR 947. It will be recalled that orthodox passing off entails the defendant representing that his product is the plaintiff's product. In many cases, reverse passing off can be explained under the ordinary rules: for example where a defendant may represent that he or she made goods which were in fact made by the plaintiff so as to pass off his own business as a branch of the plaintiff's.
The Law of Passing-Off - by Christopher Wadlow
Narayanan: Trade Mark, Trade Name and Passing Off Cases by P Narayanan
Law of trade marks and passing-off - by P Narayanan
Passing Off/Misappropriation, Volume 9, Studies in Industrial Property: Copyright Law by Kaufmann.