SELLING ONLINE IN THE UK

Running an online business often feels effortless: customers click, pay, and you deliver. But every one of those clicks can create a legally binding contract, even when you never meet or speak to the buyer. So how do courts decide when a contract is formed, what counts as acceptance, and which terms apply? Let’s break it down into the three key parts every business should understand:

• Offer & Acceptance
• Incorporation of Terms, and
• Electronic Execution & Security.

Offer and Acceptance in Online Contracts

Although the internet has no borders, every contract needs a governing law to be enforceable. In the UK, e-commerce contracts are generally governed by English contract law, as adapted by the Electronic Commerce (EC Directive) Regulations 2002 (the 2002 Regulations). The basic legal rules, offer, acceptance, consideration, and intention to create legal relations, apply online just as they do in traditional business.

A. Offer or Invitation to Treat?

This is the first and most important question. When you display products or services online, are you offering them for sale, or merely inviting customers to make an offer? Websites: Most online listings (e.g. product pages) are legally treated as an invitation to treat, not an offer. This means that when a customer clicks “Buy Now” or places items in their basket, they are making the offer, not you. The contract is only complete once your business accepts the offer, usually by sending an order confirmation email. For example, a clothing boutique website lists maternity dresses at £50. When a customer places an order and receives a “Thank you for your purchase” message, that confirmation is the acceptance that forms the contract.

Emails: When a deal is negotiated by email (for example, between two businesses), the same rules apply as in traditional correspondence. A valid offer must clearly show an intention to be bound once accepted, while a vague or conditional message is just an invitation to negotiate.

B. When is Acceptance Effective

The general rule is that acceptance by email or electronic means takes effect when it is received, not when sent. This was confirmed in Thomas v BPE, where the court held that an email acceptance arriving at 6 p.m. on a Friday was valid once received, even though it was outside normal office hours. In contrast, under the old postal rule, acceptance by letter is valid when posted. That rule does not apply online. Modern business expects instant or near-instant communication. Under the 2002 Regulations (Reg. 11), when a contract is made via a website: The customer’s order is normally the offer. The seller’s confirmation is the acceptance. Both are deemed received when the recipient can access them (not necessarily when they read them). This ensures that contracts made online have a clear legal moment of formation.

Just like in traditional business, the terms and conditions of your website or service must be brought to the buyer’s attention before the contract is made. Failure to do so could mean your terms don’t apply, and you could lose protection against refunds, returns, or liability. Courts will apply the same tests as in offline contracting:

• Were the terms reasonably brought to the other party’s notice?
• Was there a consistent course of dealing using those terms?
• Were both parties aware of and agree to them?

For online contracts, it’s best practice to use “click-wrap” agreements — where the buyer must tick a box confirming they accept your terms. “Browse-wrap” terms (hidden in a link at the bottom of a webpage) are much riskier, as they often fail to bind customers. For example, a startup’s website includes a refund policy hidden in small print at the bottom of the checkout page. A customer disputes a purchase and claims they never saw it. The court may rule that the term was not incorporated, leaving the seller unprotected.

Electronic Execution, Encryption & Security

Most online contracts don’t require a wet signature (i.e., pen-and-paper). However, when a signature is required by law or agreement, electronic signatures are legally valid in the UK under, The Electronic Signatures Regulations 2002 (SI 2002/318), based on Directive 1999/93/EC; The Electronic Communications Act 2000, Part II.

This legislation recognises that an electronic signature, such as clicking “I Agree,” typing your name, or using a secure digital certificate, can have the same legal effect as a handwritten signature. Courts have confirmed this in cases such as Mehta v J Pereira, which held that an email can satisfy the legal requirement for “writing” and sometimes for “signature,” depending on how it’s sent. Furthermore, online business also raises major security concerns, particularly around payment and identity. The law expects businesses to take reasonable care to protect customers’ data and prevent fraud.

Encryption (scrambling data to make it unreadable to outsiders) plays a crucial role here. It helps ensure:

• Confidentiality of customer information (especially bank details).
• Validity of electronic signatures and certificates.
• Trust in your e-commerce platform.

While encryption itself is a technical issue rather than a legal one, regulators expect all online traders to implement secure systems to prevent data breaches and fraud.