Glossary
Waiver
A waiverA waiver is a choice not to enforce a right this time, without rewriting the contract. Accepting late work once does not, by itself, kill a time-is-of-the-essence clause if a no-waiver line is present. Waiver is not a variation: Rock Advertising Ltd v MWB [2018] UKSC 24 still requires the agreed method for a change of terms.More in the glossary is a choice not to enforce a right this time, without rewriting the contract. Accepting late work once does not, by itself, kill a time is of the essence“Time is of the essence” makes a deadline a condition of the contract. In England and Wales a party who misses that deadline is then in breach of a condition, so the other side can terminate and claim damages even if the delay is short.More in the glossary clause if a no-waiver line is present. Waiver is not a addendumAn addendum is a short, written change to an existing contract, signed by both sides so the original terms stay the same except for what the addendum updates.More in the glossary: Rock Advertising Ltd v MWB [2018] UKSC 24 still requires the agreed method for a change of terms.
Last updated 28 October 2026
The usual fight: the client accepted a late milestoneA milestone is a defined point in a project, often tied to a deliverable and a payment.More in the glossary in May, then tries to terminate for a late milestone in June under time is of the essence. Without a no-waiver clause, the May acceptance can be used as a waiver or as evidence that time was no longer essential. With one, May is a one-off. A variation would have been needed to change the dates for good.
We put a no-waiver line in the boilerplate. Lex will not treat “fine, send it Monday” as a signed change of the timetable. If you mean to change the date, issue an addendum. If you mean to let this one slip, say so and keep the clause.
Does accepting late work waive the clause?
It can, if the paper is silent. A no-waiver clause says that a failure or delay in enforcing a right is not a waiver of that right or of a later breach. Courts generally give those clauses effect. They do not let you spring a trap: if you have clearly elected to affirm, you have affirmed.
Is a no-waiver clause effective?
Yes, as a starting point. It stops a single indulgence rewriting the paper. It does not stop a later signed variation, and it does not stop an election you have already made in clear terms. Write that any waiver must be in writing and signed if you want that extra lock.
How is waiver different from a variation?
Waiver leaves the term in place and declines to enforce it this time. Variation changes the term. Rock Advertising [2018] UKSC 24 is about variation formalities, not about waiver. Do not use a waiver email to rewrite the fee; that needs the variation method.
Can we waive in advance?
A standing waiver of a future breach is close to a variation and will be read that way. Waive the breach that has happened, in writing, and keep the clause for next time. An advance waiver of confidentiality or of the liability cap is a rewrite, not a courtesy.
A worked example
A paper says time is of the essence on the launch date and that no failure to enforce a right is a waiver. The studio accepts a two-day slip in May, in an email that says “this once, the clause stands.” In June the client is a week late on assets. The studio serves a [cure](/glossary/cure-period) notice. The May email is not a variation of the date and is not a waiver of June.
How it shows up in a contract
Sample wording · our own drafting
A failure or delay in exercising a right under this agreement is not a waiver of that right or of any later breach. Any waiver must be in writing and signed by the waiving party, and applies only to the breach it names. This clause does not affect the formalities for a variation.
In Plain English
Letting something go once does not rewrite the contract or forgive the next time. If we waive, we will do it in a signed note that names that breach only. Changing the deal still needs a proper variation.
Common mistakes
- Accepting late work in silence and then being told you waived time is of the essence.
- Using a waiver email to change the fee or the scope — that is a variation.
- Drafting a no-waiver clause and then clearly electing to affirm a repudiatory breach.
- Giving a standing waiver of future breaches, which a court will treat as a rewrite.
What the legislation says
Where a contract contains a clause that variation must be in writing and signed by or on behalf of the parties, an oral variation is not effective. The parties have bound themselves to a specified method of variation and the court gives effect to it.
Source: Rock Advertising Ltd v MWB Business Exchange Centres Ltd, [2018] UKSC 24Checked 28 October 2026Pending lawyer review
Sources
- Rock Advertising Ltd v MWB Business Exchange Centres Ltd, [2018] UKSC 24Checked 28 October 2026Pending lawyer review
Frequently asked questions
What is a waiver in a contract?
A choice not to enforce a right this time, without changing the term. A no-waiver clause stops one indulgence rewriting the paper.
Does accepting late work waive the timetable?
It can, if the paper is silent. A no-waiver clause, plus “this once”, keeps the clause for next time. See /glossary/time-is-of-the-essence.
Is a no-waiver clause effective?
Yes, as a starting point. It does not undo a clear election you have already made, and it does not replace the variation method.
How is waiver different from a variation?
Waiver leaves the term in place. Variation changes it. Rock Advertising [2018] UKSC 24 is about variation formalities. See /glossary/variation-clause.
Related
The legal wording governsLast reviewed 28 October 2026Pending lawyer review