• Mutual love and affection is not sufficient consideration: it was so held inBret V.
J.S. and illustrated by Thomas V. Thomas.
• Consideration must be legal: the act of promise offered by the promise must be lawful. Illegal consideration invalidates the contract.
• Consideration must not be past: as a general rule past consideration is not sufficient to support a contractual claim, as there is no mutuality. The decisions in reMcArdlesCase and Roscorla V. Thomas are illustrative of this position.
However, in certain circumstances, past consideration is sufficient to support a contractual claim.
• Consideration must be something of value in the eye of the law: this rule means that consideration must be real though it need not be adequate. It must be sufficient. In Thomas V. Thomas, the one pound Mrs. Thomas to remain in her late husbands house was sufficient consideration.
• Consideration must flow from the promisee: the person to whom the promise is made provides consideration and by so doing becomes party to the contract. This is the doctrine of privity of contract as exemplified by the decision in Dunlop V. Selfridge and Tweddle V. Atkinson. However, the doctrine of privity of contract has many exceptions.
• Consideration must be something in excess of a public duty: put in the alternative
performance by the plaintiff of a public duty imposed upon him by law is not sufficient consideration for a promise. As was the case in Collins V. Godefroy. However, doing some more amounts to consideration. As was the case in England V. Davidson.
• Consideration must be something in excess of an existing contractual obligation:performance of an existing contractual obligation is not sufficient consideration for a promise. The decision in Stilk V. Myrik is illustrative of this position. However, doing something more amounts to consideration as was the case in Hartley V. Ponsonby.