Contract law (2022): Contract formation: mirror image rule + invitation to treat + firm offer

In the law of contracts, the mirror image rule, also referred to as an unequivocal and absolute acceptance requirement, states that an offer must be accepted exactly with no modifications. The offeror is the master of their own offer. An attempt to accept the offer on different terms instead creates a counter-offer, and this constitutes a rejection of the original offer.

United States.

In the United States, this rule still exists at common law. However, the Uniform Commercial Code ("UCC") dispenses with it in § 2-207. (but it can also be argued that § 2-207(1) enforces the mirror image rule) Therefore, its applicability depends upon what law governs. Most states have adopted the UCC, which governs transactions in goods. Contracts for services or land, for example, would not be governed by the UCC. The 2nd restatement of contracts also provides that when parties have not agreed to an essential term, "a term which is reasonable in the circumstances is supplied by the court." However, it may not be possible for a reasonable term to be supplied by the court.

England.

The English common law established the concepts of consensus ad idem, offer, acceptance and counter-offer. The leading case on counter-offer is Hyde v Wrench . The phrase "Mirror-Image Rule" is rarely (if at all) used by English lawyers; but the concept remains valid, as in Gibson v Manchester City Council , and Butler Machine Tool v Excello.

An invitation to treat (or invitation to bargain in the United States) is a concept within contract law which comes from the Latin phrase invitatio ad offerendum, meaning "inviting an offer". According to Professor Andrew Burrows, an invitation to treat is:

"...an expression of willingness to negotiate. A person making an invitation to treat does not intend to be bound as soon as it is accepted by the person to whom the statement is addressed."

A contract is a legally binding voluntary agreement formed when one person makes an offer, and the other accepts it. There may be some preliminary discussion before an offer is formally made. Such pre-contractual representations are known variously as “invitations to treat”, “requests for information” or “statements of intention”.

True offers may be accepted to form a contract, whereas representations such as invitations to treat may not. However, although an invitation to treat cannot be accepted it should not be ignored, for it may nevertheless affect the offer. For example, where an offer is made in response to an invitation to treat, the offer may incorporate the terms of the invitation to treat (unless the offer expressly incorporates different terms). If, as in the Boots case (described below) the offer is made by an action without any negotiations—such as presenting goods to a cashier—the offer will be presumed to be on the terms of the invitation to treat.