An action for passing off is flexible and is not confined to any particular means of misrepresentation. Doing of anything which would lead customers to think that there is a connection between the plaintiff's wares, services or business and the wares, services or business of the defendant, where such a connection does not exist may be actionable. For example, it is actionable to misrepresent by way of a false endorsement that defendants' activities were authorized by the plaintiff.

The plaintiff is not required to show an intention to deceive, but if intention is shown it is evidence which tends to show that a misrepresentation has been made.

The alleged misrepresentation must be considered from the point of view of an "ordinary" member of the public and "average" customer. The average customer would take ordinary care in purchasing the goods they need, and, if desiring a particular brand, would take ordinary precautions to see that they get it.

The attention and care taken by the average customer may vary depending on the nature of the product being purchased. A customer will probably not exercise the same care in selecting goods from a supermarket shelf as they would when choosing a luxury item.

The application of these principles is shown in a recent English case. In that case, a U.S. company sold yogurt in the United Kingdom which it described as Greek yogurt but which was made in the United States. The plaintiffs sold yogurt in the United Kingdom in association with trade marks they owned as well as the phrase Greek Yogurt. Their yogurt was made in Greece. After a lengthy trial, the judge concluded that sufficient goodwill was shown to be attached to the phrase Greek yogurt amongst customers who believed that it was made in Greece and that this mattered to them. As a result, the use of "Greek yogurt" to describe yogurt not made in Greece involved a material misrepresentation. The existence of small print on the back of the packaging of the defendant's containers to indicate the product was made in the United States was not sufficient to disabuse consumers with respect to the misrepresentation that is was Greek yogurt. Therefore, the action was successful.