A valid contract requires a definite offer by one party and an unqualified acceptance by the other. The rules governing offer and acceptance determine when a binding agreement is formed.
Contracts Act 2010, Sections 2-10
A unilateral offer to the world at large can be accepted by performance. The advertisement constituted an offer, not an invitation to treat.
A counter-offer destroys the original offer. The plaintiff could not revert to the original offer after making a counter-offer.
When drafting contracts, ensure the offer is specific about price, quantity, and delivery terms. Vague terms can render a contract unenforceable.
Always distinguish between an offer and an invitation to treat. Goods displayed in a shop window are an invitation to treat (Fisher v Bell), not an offer.
