Verbal instructions in construction: binding or not, and how to get paid for them

Published 21 July 2026 · Updated 10 October 2026 · VariationFlow

A plain-English guide to verbal site instructions for UK subcontractors: whether an oral instruction is binding, what JCT and NEC4 actually require, how to confirm a verbal instruction (CVI) so it sticks, what the Supreme Court said about "no oral modification" clauses, and the on-site habits that turn "we’ll square it up later" into money.

“Can you just take the vinyl on through into the corridor while you’re at it? We’ll square it up later.” It is said in thirty seconds, the extra work takes a day and a half of labour and materials, and nothing is written down. Months later the final account lands and that day and a half is nowhere in it, because as far as the paperwork is concerned, it never happened. Verbal instructions are how most variations start on UK sites, and unproven verbal instructions are how most margin quietly leaves a subcontract.

Is a verbal instruction binding?

In principle, yes, English law does not generally require an instruction to be in writing to create an obligation, and an oral variation instruction can be perfectly valid between the parties. But that is the wrong question. The questions that decide whether you are paid are: does your contract give a verbal instruction any effect, and can you prove, months later, against a commercial team with no memory of the conversation, who said what, when, and what was done as a result? A binding instruction you cannot prove is worth the same as no instruction at all.

What the standard forms actually say

Most standard forms are deliberately hostile to purely verbal instructions, because employers do not want to pay for scope nobody in their office authorised.

• JCT (SBC and its sub-contracts): instructions are to be issued in writing. An instruction given orally has no immediate effect until it is confirmed in writing, the confirmation machinery and its timescales are set out in the conditions, and the cautious working assumption is that an unconfirmed oral instruction is an unpaid one.
• NEC4 (ECC and its subcontract): clause 13.1 requires each instruction to be communicated “in a form which can be read, copied and recorded”. A change shouted across a corridor is not a communication under the contract at all until it exists in writing.
• NEC4 compensation events: clause 61.3 gives a notification window, seven weeks from becoming aware on the subcontract and eight on the main contract, and missing it can bar the claim entirely where notifying was your obligation. A verbal change you sat on is a wasting asset.
• Bespoke sub-contracts are usually stricter, not looser: many make a written instruction from a named person a condition precedent to any payment for varied work. Read yours before you rely on anything said out loud.

The confirmation of verbal instruction (CVI)

The fix has existed for as long as the problem: if the instruction was verbal, you make it written. A confirmation of verbal instruction is a short notice from you to the instructing party recording what was said, and it flips the evidential burden. Instead of you proving months later that the conversation happened, they must reply at the time saying it did not. Silence in the face of a contemporaneous CVI is a very uncomfortable position to dispute an account from.

• Send it the same day. A CVI a fortnight later looks like an invention; one sent from site at 2pm about an 11am conversation reads as a record.
• Name names: who gave the instruction, to whom, where and when.
• Describe the work, and where you can, the expected cost and time effect, or state that both will follow.
• Ask for the formal paperwork: “please issue your written instruction / compensation event notification for the above”.
• Serve it the way the contract requires: the notices clause may specify addresses or systems, and a WhatsApp to a foreman may not qualify.

“We’ve always done it on a handshake”

It is tempting to assume a course of dealing rescues you, that because verbal changes were honoured on the last three jobs, they must be honoured on this one. Do not bank on it. In Rock Advertising v MWB (2018), the Supreme Court held that “no oral modification” clauses mean what they say: where the contract requires changes to be agreed in writing, an oral change is generally ineffective, however clearly both sides agreed it on the day. Waiver and estoppel arguments exist, but they are expensive, uncertain, last-resort litigation positions. A CVI costs two minutes.

When they will not put it in writing

A refusal to confirm is information. If the person who said “just crack on” will not put their name to an instruction, the employer may be intending to treat the work as contract scope, or not to pay for it at all. Your options, in rough order: confirm it yourself by CVI and proceed if the commercial risk is tolerable; escalate above the individual to the contract administrator or commercial lead; or, where the contract makes a written instruction a condition of payment and the sum is significant, decline to start until the instruction exists. “We’ll square it up later” is not an instruction, it is a request for free credit.

The playbook for the moment it happens

• Capture it there and then: who instructed it, the words used, date, time and location, with photos of the affected area before you start.
• Send the CVI the same day, and chase the formal instruction until it arrives.
• Record the resource as you go: labour hours, materials and plant, dayworks-style, signed where you can get a signature.
• Price it promptly and submit the quotation before the work disappears into the general progress of the job.
• Track the contract clocks: NEC’s notification bar, seven weeks on a subcontract against the main contract’s eight, your sub-contract’s own timescales for confirming oral instructions, and every payment-cycle deadline that follows.
• Photograph completion too: an as-built record of the varied work closes the evidential loop.

This is precisely the gap VariationFlow was built for: an operative captures the instruction on site in about a minute, photos, GPS, timestamp, who gave it, a signature where you can get one, and the system generates the confirmation, prices the variation and chases it through the payment cycle while the contract clocks are tracked for you. However you do it, do it at the time: contemporaneous records are the difference between a variation and an anecdote. This guide is general information, not legal advice, for a significant dispute over an unconfirmed instruction, involve a construction solicitor or claims consultant early.