Change Order in United Kingdom: Template and Key Clauses (2026)

A change order is a document that formally modifies an existing contract when something agreed has to change: the scope of work grows or shrinks, the price moves, or the time for completion shifts. In the United Kingdom this is more often called a variation, especially in construction, and the contract itself usually sets out how variations must be instructed, valued and agreed. A change order is not a new contract; it is a controlled amendment to the one you already have, recorded in writing before the work is done so there is no argument later. This guide covers what a UK change order does, its key clauses, the UK legal points, and a working skeleton. It is general information, not legal advice; confirm a real matter with a UK lawyer. ## Why change orders (variations) exist Projects change. A client asks for extra work, a site condition differs from expectation, costs rise, or a date slips. Without a variation, the contractor either does the extra work for free or stops and argues, and the client is unsure what they are paying for. The change order answers four questions in writing: what is changing, how much more or less it costs, how it affects the programme, and that both sides agree. Doing this before the work starts is what prevents disputes. ## Key clauses in a UK change order - Reference to the original contract. Identify the main contract by name and date, so it is clear what is being varied.

• Change order or variation number. Sequential numbering, because projects often have many.
• Description of the change. Precisely what work is added, removed or modified, in enough detail that a third party could understand it.
• Reason for the change. Client instruction, unforeseen condition, design change or error, which can affect who bears the cost.
• Valuation. The price change and how it was assessed: agreed lump sum, the contract's rates and prices, or a fair valuation. UK standard forms set out valuation rules.
• Programme and time impact. Any change to the completion date and whether an extension of time is granted.
• Effect on the rest of the contract. A statement that all other terms of the original contract remain in force.
• Authority. Signatures or instruction by the person authorised under the contract to issue variations, with the date.
• Reservation of rights. Whether the parties reserve any claims, for example for loss and expense or cumulative delay. ## Local-law points that matter in the United Kingdom - The contract's variation clause controls. UK construction and services contracts contain a variations clause setting out who may instruct a change, how it is valued and how time is adjusted. Follow it exactly; work done outside the clause may not be payable.
• Standard forms. UK construction commonly uses standard suites such as JCT (Joint Contracts Tribunal) and NEC (the NEC4 Engineering and Construction Contract). JCT handles changes through variation instructions and valuation rules; NEC uses the compensation event mechanism, which combines cost and time assessment. Use the mechanism your contract is built on.
• Written instructions. Variations should be instructed in writing by the authorised person (for example the contract administrator or project manager). Oral instructions are a common source of UK disputes; many contracts require written confirmation before the contractor proceeds.
• Entire-agreement and no-oral-variation clauses. Many UK contracts say they can only be varied in writing and signed, and the UK Supreme Court has confirmed such clauses are generally effective, so do not rely on an oral or informal variation.
• Consideration and deeds. A variation generally needs consideration to be binding, unless the contract is executed as a deed; where there is doubt, parties often execute the variation as a deed.
• Extensions of time and loss and expense. Under JCT and NEC, a change can entitle the contractor to more time and money, assessed under the contract's rules, so address the programme impact, not just the price. ## A simple drafting skeleton 1. Project and parties

2. Reference to the original contract (name and date)
3. Change order or variation number and date
4. Description of the change in scope
5. Reason for the change
6. Valuation and how it is assessed
7. Revised contract sum
8. Programme and time impact, and any extension of time
9. Statement that all other contract terms remain unchanged
10. Reservation of rights or settlement of related claims
11. Authorised instruction or signatures and date Give the most attention to the scope description, the valuation basis and the time impact, because vagueness in any of those is what turns a variation into a dispute. ## Common mistakes to avoid - Doing extra work on an oral instruction when the contract requires a written variation.

• A scope description so vague the parties disagree about what was covered.
• Not following the contract's variation or compensation-event mechanism, so the change may not be payable.
• Agreeing the price but ignoring the programme, so the contractor is later blamed for a delay the change caused.
• Relying on an informal variation where a no-oral-variation clause, or the need for a deed, applies. ## Keeping changes under control across a project Projects accumulate many variations, each shifting the scope, price and programme, and the real risk is losing track of the current state of the contract after a dozen amendments. An AI contract workspace can keep every change order linked to the main contract, show how the scope and sum have moved, and track approvals and dates in one place. Adira is built for this: one workspace tuned to your company, built on Claude, with clause-level editing in plain English, a diff of what changed, per-clause risk review and a live activity timeline, plus embedded e-signing. It is India-first today with the United Kingdom and other jurisdictions on its roadmap, so verify local depth before relying on it for UK law. More at Adira. The guidance above stands on its own. ## Bottom line A UK change order, or variation, is a controlled amendment that records a change in scope, price or time before the work is done. Reference the original contract, number it, describe the change precisely, value it under the contract's rules, and set out the programme impact and any extension of time. Follow the contract's own variation or compensation-event mechanism and get the change instructed or signed in writing, because oral variations are a frequent source of UK disputes, and watch for no-oral-variation clauses and the need for a deed.