National Provincial Bank v Ainsworth [1965]

Key Points of the Case:

• Proprietary Character of Rights: The case established a foundational approach to determining if a right has a proprietary character.

• Lord Wilberforce's Four-Fold Test: To establish an interest in land, the right must meet the following criteria:

1. Definable: The right must be clearly defined.

2. Identifiable by Third Parties: It should be capable of being identified by third parties.

3. Capable of Assumption by Third Parties: The right should be such that it can be assumed by others.

4. Degree of Permanence and Stability: The right must have some degree of permanence and stability.

• Open-Ended Criteria: The terms used in the test are very broad, allowing for a flexible interpretation.

• Circular Argument: The criteria imply that a right is proprietary only if it can affect third parties, leading to a circular reasoning where the proprietary nature of a right is assumed only if it has already been treated as proprietary.