Contract clause
No oral modification clause: changes only in signed writing
A no oral modification clause says the contract can only be changed in a stated form, usually in writing signed by both parties. In the UK, the Supreme Court held in Rock Advertising v MWB that such a clause is effective, so an oral agreement to vary the contract does not bind.
Business relationships run on phone calls and quick agreements. A no oral modification clause says none of that changes the contract unless it is written down and signed, and since 2018 English law takes the clause at its word.
Indunil Asanka · Co-founder
4 min read · Published
Sample clause
Written for an office licence between Jewellery Quarter Workspace, a fictional Birmingham serviced office provider, and a design studio licensee.
Variation. (a) No variation of this Licence is effective unless it is in writing, refers to this Licence and is signed by an authorised signatory of each party. (b) For the purposes of this clause, an email or other electronic message is not writing signed by a party, even if it contains a typed name or an email signature block, unless it attaches a document signed by an authorised signatory using an electronic signature service. (c) The authorised signatories of the Licensor are its directors and its operations manager. The authorised signatories of the Licensee are its directors. (d) No failure or delay in enforcing a term of this Licence is a waiver of it unless the waiver is given in writing in the same way.
Sample wording, not legal advice.
Variants
Signed writing only
Most commercial contracts, where both parties want certainty about what the current terms are.
This Agreement may only be varied by a written document signed by or on behalf of each of the parties.
Email allowed with a named sender
Fast moving relationships where email is the practical way to agree changes, but only from named people.
A variation may be agreed by email if it is sent by a party's Contract Manager named in Schedule 1, expressly states that it varies this Agreement, and is confirmed by reply email from the other party's Contract Manager.
Variation by notice procedure
Long term services contracts with a change control process, where changes are proposed, priced and approved in a set form.
Any change to the Services or the Charges must be made through the change control procedure in Schedule 4 and is effective only when a Change Order in the agreed form is signed by both parties.
What to negotiate
Estoppel risk
In Rock Advertising, the Supreme Court said that a party who relies on an oral variation may, in some cases, be protected by estoppel, if the other party made an unequivocal representation that the variation was valid and the first party relied on it. That is a narrow safety valve, not a reliable route. Parties should get changes signed rather than hope estoppel applies.
Emails
Whether an email satisfies a clause requiring writing signed by the parties depends on the wording. English courts have found that an email can be writing and a typed name can be a signature, so a clause that wants to exclude emails must say so, as the sample does. Clauses that want to allow emails should say who may send them and how they must be confirmed.
Who can sign
Naming the people who can agree variations stops a project manager or salesperson from agreeing changes that bind the company. It also helps the other side know whose signature to obtain. Keep the list current, and allow it to be updated by notice rather than by a variation.
The risk of leaving it out
Without a no oral modification clause, a contract can be varied informally, by a conversation, an email exchange or conduct, and disputes then turn on who said what. The clause does not stop parties agreeing changes, but it forces them to record those changes, which protects both from arguments about the current terms.
The UK, Australian and US positions
United Kingdom: in Rock Advertising Ltd v MWB Business Exchange Centres Ltd in 2018, the Supreme Court held a clause requiring variations to be in signed writing effective, so an oral agreement to reschedule licence fees did not bind, subject to a narrow estoppel exception. Australia: courts have traditionally been more willing to find that parties, by their conduct or a later agreement, varied a contract despite such a clause, treating it as something the parties can themselves vary or waive, so the clause is persuasive but less conclusive. United States: under UCC section 2-209 for sales of goods, a signed agreement excluding modification except by signed writing is effective, but an attempted modification can still operate as a waiver. Outside the UCC, many states allow oral modification despite such clauses. Law checked on 21 October 2026. This page explains how the clause works and is not legal advice.
The facts of Rock Advertising
Rock Advertising occupied office space under a licence with MWB that required variations to be in writing and signed. Rock fell into arrears and, it said, agreed by phone with MWB's credit controller to reschedule payments. MWB later locked Rock out and sued for the arrears. The Supreme Court held the oral agreement ineffective because of the clause. The sample follows the same kind of office licence, which is why it names who may sign.
Waiver as well as variation
A no oral modification clause deals with changing the contract. A party might also argue the other has waived a right, for example by accepting late payments without complaint. The sample's paragraph (d) requires waivers to be in signed writing too. Many contracts also have a separate waiver clause, and the two should be consistent.
Recording changes in practice
Agree changes in a short variation document that identifies the contract, sets out the change and its start date, and is signed by authorised people. Electronic signature services make this quick. Keep variations with the contract, numbered in order, so the current terms can always be reconstructed.
Documents that carry this clause
Master services agreementA data consultancy and an insurer sign this once and then buy work under it for three years. It is the rare contract whose whole purpose is to make the next twenty contracts short.
Consulting agreementAn advisory firm reviews three bakeries over seven weeks. What makes this agreement useful is not the fee clause but the two clauses that say what the advice is not.
Licence to occupy template for desk space without a leaseA licence to occupy gives someone permission to use space without giving them exclusive possession of it, which is the line between a licence and a lease. This one covers two desks in a Melbourne studio at $180 a week including GST, with fixed access hours, a right to move the desks on seven days notice, and 14 days to end it from either side.Questions people ask
Can a written contract be changed orally in the UK?
Not if it contains a clause requiring variations to be in writing and signed, following the Supreme Court's decision in Rock Advertising v MWB in 2018. Without such a clause, an oral variation can be effective. A narrow estoppel argument may sometimes help a party that relied on an oral promise.
Does an email count as writing?
It can. English courts have treated emails as writing and typed names as signatures, so whether an email satisfies the clause depends on its wording. A clause that wants to exclude emails must say so expressly; one that wants to allow them should say who can send them and how.
What is estoppel?
Estoppel is a legal principle that can stop a party going back on a clear representation that another party relied on to its detriment. In Rock Advertising, the court said estoppel might, in limited cases, prevent a party relying on a no oral modification clause, but it requires more than the oral agreement itself.
Do no oral modification clauses work in Australia?
They are given weight, but Australian courts have been more willing than English courts to find that the parties varied a contract by later agreement or conduct despite the clause, or are estopped from relying on it. Recording variations in signed writing is still the safest practice.
Is a variation signed electronically valid?
Generally yes, if the clause does not exclude it and the electronic signature identifies the signer and shows their intent. The sample expressly allows documents signed through an electronic signature service, while excluding informal emails, which gives both speed and certainty.
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Create a document with OneCraftRelated clauses
- Variation clause: the rule for changing the contract laterA variation clause sets how a contract can be changed after signing. Sample written variation wording, plus email and one sided price change variants.
- Entire agreement clause: the written contract is the whole dealAn entire agreement clause says the signed contract is the whole deal. Australian sample wording, non reliance and US integration variants, and the ACL limit.
- Waiver clause: tolerating a breach without giving up the rightA waiver clause says letting a breach slide once does not give up the right to act on it later. Sample lease wording, plus written and single instance variants.
- Electronic signature clause: agreeing in the contract how it will be signedAn electronic signature clause records that the parties agree to sign electronically. Australian sample wording plus UK, US and deeds carve out variants.
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Written and checked by the OneCraft team. Last checked .