What makes a contract legally binding in England and Wales?

A binding contract requires an offer, acceptance, consideration and an intention to create legal relations. Its terms must also be sufficiently certain. For many everyday commercial agreements, a signature is not essential, it doesn't even have to be in writing: a contract can emerge from a conversation, a chain of emails or an exchange of messages.

That is where many contract disputes begin. One party says a deal was done. The other says they were still negotiating. Before arguing about who broke the contract, you have to establish whether there was a contract to break.

The legal ingredients may sound academic, but they have very practical consequences.

Offer: was there a proposal capable of acceptance?

An offer is a proposal on sufficiently clear terms, made with the intention that it will become binding if accepted. It gives the other party something they can say yes to.

For example: “We will supply 100 units of [goods] for £5,000, delivered by 30 November.” Depending on the context, that could be an offer. “We could probably supply something like that for around £5,000” is more likely to be part of a discussion.

The distinction matters because negotiations often contain several proposals. A price is floated, the scope changes and a delivery date is discussed. Each exchange needs to be read in context to establish whether it was an offer capable of acceptance or simply another step towards a possible deal.

Acceptance: did the parties agree to the same terms?

Acceptance is an unqualified assent to all of the terms. In other words it is an agreement to the offer. It must correspond with the terms offered. A response proposing different terms will generally be a counteroffer, although a request for clarification does not necessarily reject the original offer.

“Yes, but only if you include installation for the same price” is different from accepting a supply-only offer. The parties may be close to agreement, but being close is not enough.

If a counteroffer is made, the original offer is extinguished because you have not reached that 'unqualified assent to all of the terms'. 

Acceptance generally needs to be communicated. It may be expressed in words or shown by conduct, such as carrying out work in response to an offer. You can even accept a contract, potentially, by sending a thumbs up emoji in WhatsApp.

There are exceptions and context matters, but a private decision to accept will not ordinarily create a contract. Silence alone will not generally amount to acceptance.

Consideration: what is being exchanged?

Consideration is what each party gives or promises in exchange for the other’s commitment. In a straightforward supply contract, one party promises goods and the other promises payment. In a loan agreement, the advance of money may be exchanged for a promise to repay it. If you instruct me to assist in a dispute, I promise to provide you services, you promise to pay my fees. That reciprocal obligation to do something is necessary to create a contract. 

It does not have to be money. Services, goods or a promise to do something can provide consideration. Nor does the exchange have to be financially equal: the court does not normally assess whether you negotiated a good price, rather it will try to give effect to what was agreed as far as it can. 

An ordinary contract needs a legally recognised exchange. A bare promise to make a gift will not usually be enforceable as a contract. A properly executed deed can bind without consideration, which is one reason the form of the transaction can matter.

Intention: did the parties intend to be legally bound?

The parties must intend their agreement to have legal consequences. This is assessed objectively, from their words and conduct in context. It does not depend simply on what someone later says they privately intended.

Dealings between family members, for example, to go halves on the cost of the 'big shop', will not ordinarily give rise to a contract. There is a presumption that the parties to that arrangement do not intend to sue or be sued if it goes wrong. 

Commercial dealings generally carry a presumption that the parties intend to be legally bound. That presumption can be displaced with evidence. One important example is where negotiations or a document are marked “subject to contract”. 

What does “subject to contract” mean?

Those words generally reserve legal commitment until the contemplated formal contract is concluded. They can therefore be central to whether an apparent agreement is binding.

In one matter I dealt with, a party alleged that there was a loan agreement but relied on a document marked “subject to contract”. Our position was that the document recorded proposed terms rather than establishing a concluded loan contract. The issue was not simply whether terms had been written down, but whether the parties had moved from a proposal to a binding commitment.

Parties can later agree to lift a “subject to contract” reservation, expressly or by conduct, so the full history needs to be examined. Nor does the failure to prove a contract on one document necessarily dispose of every possible claim concerning money transferred.

Certainty: are the obligations sufficiently clear?

The agreement must be sufficiently clear for the court to identify the obligations the parties undertook. That does not mean every conceivable detail needs to be written down. Some terms may be supplied by law or properly implied, but the court cannot simply invent the bargain the parties never made.

This is particularly important where negotiations unfold across meetings, calls, emails and messages. There may be no single document containing the agreement. The task is to piece the exchanges together and establish what, if anything, was agreed.

Can emails and WhatsApp messages create a contract?

Yes. Emails and messages can form a binding contract if the necessary ingredients are present. Their informality does not, by itself, prevent them from having legal effect.

Imagine a price discussed in a meeting, a scope of work sent by email and a start date confirmed by message. Those exchanges may collectively establish a contract. If the scope remained disputed, or the parties made clear that nothing would bind until a final agreement was signed, the position may be different.

The sequence matters. You need to identify which proposal was accepted, whether its terms had changed and whether the acceptance itself introduced a condition. Terms left for further agreement and the parties’ subsequent conduct may also be important.

An email saying “happy to proceed” can be powerful evidence. Its meaning still depends on what the sender was agreeing to. Pulling it out of the chain can give a misleading picture.

Can a verbal agreement be legally binding?

Yes. Many everyday commercial contracts can be made verbally, provided the necessary ingredients are present. The practical difficulty is often proving what was said and agreed but the principles of offer, acceptance, consideration and certainty are what will determine whether or not a contract came into existence. 

Emails, messages and evidence of what the parties did afterwards may help establish the terms of a verbal agreement. Keeping a written record is therefore valuable even where a signed contract is not legally required.

Does a contract have to be signed?

Generally, no. For many commercial agreements, a signature is not a legal prerequisite. Some transactions do have particular legal formalities, however, and parties can themselves make signature a condition of being bound.

Equally, a document headed “agreement” does not answer every question. You still need to identify the parties, their obligations and whether they committed to them. Capacity, authority and legality can also affect enforceability.

How can businesses reduce the risk of a contract dispute?

The best time to remove uncertainty is before money changes hands or work starts:

• Record the agreed scope, price and timing.

• Make clear whether you are committing now or reserving commitment until a formal contract is concluded.

• Keep the emails, messages and other records that explain how agreement was reached.

• If terms change, record what changed and whether both parties agreed to it.

If a dispute does arise, start with the ingredients. Establish what was offered, what was accepted, what each party gave or promised, and whether the parties intended to be bound on sufficiently clear terms. That provides the foundation for assessing your rights and deciding what to do next.

Need help with a disputed agreement?

If you are dealing with a disputed agreement, an alleged loan or negotiations that have become a contractual dispute, I can help you assess the evidence and your options. I offer a free, no obligation initial 30-minute consultation.  Contact me here to arrange an initial discussion.