Waleed Tariq Academy homeNEC Case Law, Clause by Clause · Changing the contract
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NEC Case Law, Clause by Clause · Module 1 · Lesson 3 of 4

Changing the contract

8 screensAbout 6 minutes

Why it matters

Does a director's remark that a day late will not matter stop the deduction?

A remark at a meeting, and nothing written down.

26 May 2027Completion, one day late
GBP 4,000 for that one day
Suppose an Aldermere Water director said it at a progress meeting on 12 May 2027.

Source: ECC 12.3, X7.1.

The rule

Any other change needs both Parties to sign it

Only the sign. Dana, the Project Manager, cannot.

  1. 1

    Do the conditions provide for the change?

    If yes:
    It takes effectSuch as a change
    If no, go on to question 2.
  2. 2

    Is it “agreed, confirmed in writing and signed by the Parties” (12.3)?

    If yes:
    It takes effect
    If no, go on to the outcome.
  3. No effect

Source: ECC 12.3, 14.3.

The rule

Clauses that demand signed changes work

12.3 is a . The followed Rock in 2026 (Module 8).

The facts

Rock said a phone call agreed new payment dates.

Held

Such clauses stop informal deals and control who agrees changes.

needs clear words or conduct showing the change was meant to bind.

Source: Rock Advertising v MWB (2018). ECC 12.3.

The rule

Shared practice can bind for the past

NEC3 .

The dispute

  1. Jul 2009 to Jan 2010About 13,600 orders on agreed codes.
  2. Jan 2010Shoreline seeks about GBP 300,000.

Three judgments

  1. 17 Jan 2013TCC: no strike out.
  2. 5 Jun 2013Court of Appeal: agreed.
  3. 20 May 2015Trial: protects earlier months.

Source: Mears v Shoreline (2013 and 2015). NEC3 TSC 12.3, 12.4.

See it on the project

The remark changes nothing, so the GBP 4,000 deduction stands

A remark alone is no estoppel either.

May 2027The director's remark on 12 May 2027, the Completion Date of 25 May and Completion on 26 May 2027.MayJuneAldermereWaterMerrowValeCompletion Date1 What if2 Completion
  1. 112 MayWhat ifAldermere Water What if: a director says a day late will not matter. Nothing written, nothing signed (12.3).
  2. 226 MayCompletionMerrow Vale Completion, one day after the Completion Date. Aldermere Water deducts GBP 4,000 (X7).
112 MayAldermere Water

…

Source: ECC 12.3, X7.1. Rock Advertising v MWB (2018).

Try it

Predict what each court held, then tap to check

Say yes or no before you tap.

Rock: did the phone call vary a licence that needed signed changes?

No. The clause was effective, so the oral deal had no effect.

Rock: is estoppel gone?

No. It stays a safeguard, but needs clear words or conduct showing the change was meant to be valid.

Mears: could Shoreline claw back the months before its notice?

No. Going back on the shared codes for that time would have been unjust.

Mears: after the notice, did the codes still bind?

No. Notice ended the shared basis from then on.

Source: Rock Advertising v MWB (2018). Mears v Shoreline (2015).

Try it

Sort each step: does it take effect or not?

Ask two questions each time. Do the conditions allow it, and did both Parties sign?

Step 1 of 6

…

Source: ECC 12.3, 14.3, 60.1(1), 63.2, X16.

Recap

Get every change signed, or end an informal practice by notice

Remarks and minutes change nothing. A signed change does.

On Monday at work

  • Check first whether the conditions provide for the change.
  • Put any other change in one document both Parties sign (12.3).
  • When practice drifts from the contract, sign it or end it by notice.

In the Toolkit: NEC4 ECC Notice Letters (zip) Members

Next lesson: The whole agreement

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Independent course material. It is not published or endorsed by NEC, and it is not legal advice. Clause references are to the NEC4 Engineering and Construction Contract, June 2017 with amendments January 2023. Cases decided under an earlier edition are matched to the NEC4 clause that does the same job. The worked examples and their people are invented. Short quotes from NEC4 (© NEC 2017) and the FIDIC Red Book (© FIDIC 2017) are used for review and comment. Read the full clauses in your own copy of the contract.

Source: ECC 12.3, 63.2.

Go deeper (optional)

Write a change both Parties can sign

Name each Party exactly.

What to writeSigned change under clause 12.3

Aldermere Water and Merrow Vale Civils Ltd agree:

[clause or entry] reads [new words] from [date]

For Aldermere Water: [name, position]

For Merrow Vale Civils Ltd: [name, position]

No Toolkit letter: both Parties sign this.

Source: ECC 12.3.

Go deeper (optional)

Two points on clause 12.3 that no court has settled

Open questions for later.

Does estoppel still get round 12.3 after Rock?

Untested on the ECC. Mears says months of shared practice bind for the past. Rock sets a high bar, because such clauses give certainty and control who may agree changes. That point weighs more where only signed changes count.

Mears (2015). Rock (2018)

What counts as signed under 12.3?

The ECC does not say. The safe course is a change document signed for each Party by someone with authority.

ECC 12.3

Source: ECC 12.3. Mears (2015). Rock (2018).