Chapter 5: The certifier

The certifier does two different kinds of work, and the law treats them differently. Jackson J drew the line in Scheldebouw v St James Homes, a 2006 decision of the Technology and Construction Court (TCC). Most of the time the certifier is the employer's agent. It passes on the employer's instructions and gives effect to its choices, and in that role it owes the employer the ordinary duties of an agent (Scheldebouw [21], [24]). Some of its work is different in kind. It decides matters where the contractor and the employer have opposing interests: extensions of time, loss and expense, interim payments, practical completion and the final balance. For those it must act fairly between the two.

Why should the employer's own agent have to be fair to the contractor? The answer lies in what the contractor agreed to. It accepted that a person chosen and paid by the other side would decide its time and its money during the job. No contractor would sign up to that if the person could simply favour the employer, because its rights would then be whatever the employer said they were. So the law reads a duty of fairness into the arrangement. Lord Reid reached the same result in Sutcliffe v Thackrah (House of Lords, 1974). It must therefore be implicit in the owner's contract with the architect that the architect reaches such decisions fairly, holding the balance between client and contractor. His list of those decisions included whether the contractor should be allowed extra time.

The result is a paradox that the courts accept openly. The certifier is not independent. Lord Hoffmann said in Beaufort that the architect is the employer's agent and can hardly be called independent. Yet on the second kind of decision it must behave as if it were. Jackson J put the two together: the certifier is not an independent person, but has a duty to act in an independent manner (Scheldebouw [26], [30]). He then set out three propositions that are now the starting point under any standard form. The contract decides the certifier's role and duties. The certifier is not, and cannot be treated as, independent of the employer. And on decisions between the parties it must use its professional skill and do its best to reach the right decision, not one that favours the employer (Scheldebouw [34]).

Scheldebouw is a first-instance decision, which binds no other court. But it rests on House of Lords authority and it has been followed. In ICI v Merit Merrell (TCC, 2017) Fraser J applied the same analysis to an NEC3 contract, and indeed to most if not all of the standard contract forms. Under many contracts an extension is not a certificate at all, and nothing turns on that (Scheldebouw [33]).

Who the certifier is depends on the form. The JCT Design and Build Contract 2016 gives the extension decision to the Employer itself (cl 2.25.1). In practice the Employer's Agent usually makes it, because Article 3 gives the agent full authority to act for the Employer under the conditions, unless the Employer says otherwise. Under the older JCT building contracts the architect decides (Walter Lilly [125]). Under NEC4 it is the Project Manager. NEC calls the employer the Client, and the Client may replace the Project Manager after telling the contractor who the replacement is (cl 14.4). Under the FIDIC Red Book 2017 it is the Engineer. The SCL Protocol, the industry's guidance on delay, calls the person the contract administrator, or CA. Chapter 16 compares the forms.

Fairness for a certifier is narrower than fairness for a judge, and the reason is the job. A certifier sits on the employer's side of the table by design. It decides many things quickly while the work goes on. And any of its decisions can be reopened later by a proper tribunal. Holding the certifier to courtroom standards would slow the job without adding much protection. So the law asks for honesty, skill and an even hand, not a hearing.

The Court of Appeal decided the point in Amec v Secretary of State for Transport (2005). The rules of natural justice bind judges and arbitrators, but not an Engineer giving a decision under clause 66 of the ICE conditions ([46]). That was a decision on a formal dispute referred to the Engineer. If even that decision needs no hearing, an ordinary extension decision needs none either. Megarry J had said the same in 1971 of an architect's notice of default, the first step towards termination, unless the contract so provides (Hounslow v Twickenham Garden, applied in Amec).

Fairness still means something. May LJ would not be coy about saying that the Engineer has to act fairly, so long as fairness is flexible and fitted to the occasion ([47]). One practical rule follows. If the certifier takes representations from one side beyond the application itself, fairness may require it to invite the other side to answer. May LJ added that this is not a straitjacket in every case ([48]). If I were certifying, I would let the contractor see and answer anything the employer sent me about its claim.

The real test is the one Jackson J set. Judges have described the certifier's duty with several words: independent, impartial, fair and honest. The words overlap but are not synonyms ([34]). What they come to is this.

That test explains the rest. A certifier who applies a policy, such as cutting every claim by a third, has not tried to reach the right decision on the application in front of it. A certifier may take advice, and the contract may require it to consult, but consulting others does not water down the duty ([35]).

On most forms the certifier's task during the job is a forecast. An event happens that the contract puts at the employer's risk. The contractor gives notice and particulars (chapter 4). The certifier decides whether the event is one the contract lists, whether it is likely to delay completion beyond the current completion date, and by how much. It fixes a new date and tells the contractor. Akenhead J explained in Walter Lilly v Mackay (TCC, 2012) that a date fixed during the job lets the parties and the Architect plan for the rest of the job.

The JCT wording shows the task. Under the Design and Build Contract 2016 the trigger is a Relevant Event that is likely to delay completion beyond the Completion Date. The Employer then shall give an extension of time by fixing a later date that it estimates to be fair and reasonable (cl 2.25.1; Mace [44]). The test is delay to completion, not delay to some activity. An event that delays an activity with float, but does not move completion, earns no extension. Chapter 2 explains float and the critical path; chapter 3 explains the rule.

Walter Lilly adds three points about how the certifier goes about it. The duty is not optional: the contract says "shall". Both parties need a correct date, because liquidated damages run from it. No method is prescribed, so the certifier simply has to do the best it can ([125]). And "fair and reasonable" does not license a discount. If an event has in fact delayed the works by 10 weeks, a lesser extension would be an extraordinary state of affairs ([363]). Chapter 3 deals with that phrase.

Doing the best it can still means reasoning, not guessing. In John Barker v London Portman Hotel (1996) the court accepted that assessing a fair and reasonable extension involves judgment. But that judgment must be fairly and rationally based (as quoted in Balfour Beatty v Lambeth, TCC, 2002). I would work from the programme current at the notice, the particulars and the records, and write down the reasons.

Timing and form come from the contract. Under DB 2016 the Employer must decide as soon as reasonably practicable and in any event within 12 weeks of receiving the required particulars (cl 2.25.2). The 2024 edition cuts the period to 8 weeks. JCT withdrew the 2016 edition on 31 March 2026. Many live contracts still use it, and the clauses quoted here are DB 2016; the numbers do not all carry across. The decision must also state the extension attributed to each Relevant Event (cl 2.25.3.1). Leaving that out does not take the decision outside the contract. In Clerkenwell Lifestyle v HG Construction (TCC, 2026) the argument that it did placed far too much weight on a provision that may easily be overlooked ([83]).

The SCL Protocol adds good practice. It discourages a "wait and see" approach to extensions. When granting or refusing one, the certifier should give the contractor enough information to understand the reasons (SCL 4.4). Where the contractor has not supplied the information needed, the Protocol expects the certifier to award only the minimum extension that can be justified at the time. Its reason is that an extension is difficult if not impossible to withdraw once granted (SCL 4.5). This is guidance, not law, but it fits the one-way review under JCT.

NEC4 and FIDIC build the process differently. Under NEC4 the contractor quotes for the change to the prices and the completion date, and the Project Manager replies within two weeks of the quotation (cl 62.3). If no quotation arrives in time, the Project Manager makes its own assessment (cl 64.1).

FIDIC's 2017 Red Book goes furthest. When the Engineer agrees or determines a matter, it shall act neutrally between the Parties and is not deemed to act for the Employer (Sub-Clause 3.7). It must consult both parties, make a fair determination with reasons and give notice of it within the time limits in 3.7.3. Everywhere else the Engineer is deemed to act for the Employer, except as the conditions state (3.2). So FIDIC writes the two jobs into the contract, and adds a consultation step that English law would not otherwise require.

The employer can tell its agent what to do on agency matters. It cannot tell the certifier what answer to give on a decision between the parties. The reason goes back to the bargain. The contractor's protection is the certifier's own judgment. An instruction on the answer puts the employer's judgment in its place, and the protection is gone. That is so even if the instruction cuts both ways.

ICI v Merit Merrell shows how it happens. ICI engaged the contractor on an NEC3 contract, with an outside firm, PROJEN, as Project Manager. On 8 October 2014 Mr Conrad of AkzoNobel, ICI's parent company, emailed PROJEN's Mr Barton an "official instruction". Two named AkzoNobel people would have to sign off any revised assessment before it was certified, and this goes for upwards and downwards revisions. The next day the Project Manager resigned. He said he no longer had the Employer's authority to carry out his responsibilities ([137]).

Fraser J found that he was right. The sign-off requirement took away powers that were essential to the role, and he had no option but to resign ([137]). AkzoNobel had interfered with the proper exercise of PROJEN's duties ([138]). ICI then put an AkzoNobel employee in his place, who had been acting as ICI's project manager before and was the very opposite of independent ([135]). No proper appointment was made under NEC3, and the purported appointment was a breach of contract by ICI ([139]). The result, in the judge's words: there was no Project Manager.

ICI's answer was that the contractor could always challenge the decisions. Fraser J rejected it. Dispute resolution is for when disputes have arisen, not an answer to the central operation of the contract ([133]). That is right in principle. Adjudication corrects a bad decision after the event, at a cost. The contract promised a fair decision in the first place.

An employer may go further and try to take the decisions itself. Without an express term it cannot. The reason is practical. A senior professional inside an organisation can put its interests aside. But it is harder for the organisation itself to decide against its own interests, and the contractor loses a layer of protection (Scheldebouw [45]). So Jackson J held that for the employer to be the certifier and decision-maker is so unusual that it can only be achieved by an express term ([45]). The employer there was not entitled to appoint itself ([46]). Fraser J said the same of an employer substituting its own or its parent's employee in the middle of the job (ICI [134]-[135]).

JCT Design and Build meets the express-term point head on: clause 2.25.1 makes the Employer the decision-maker. What that Employer owes when it decides is another matter.

The NEC Project Manager raised a similar question. In Costain v Bechtel (TCC, 2005) Jackson J found it at the very least, properly arguable that the Project Manager must act impartially when assessing sums due ([53]). That was on an interim injunction application, with the employer not a party to it, and he said a final decision was impossible ([52]). The firmer ground is ICI, where Fraser J applied Scheldebouw to NEC3 ([132]).

The opposite failure is silence. A certifier that never decides has failed to do something the contract requires. That does not take away the contractor's entitlement. The entitlement comes from the contract's terms and the facts; the certifier's decision is the machinery for recognising it. Where the contract does not make the certifier's decisions conclusive, the court can decide the entitlement itself. Lord Lloyd said in Beaufort that its power to open up certificates is part of the court's ordinary power to enforce the contract (270). JCT also builds in a backstop. After practical completion the certifier must carry out a final review; under DB 2016 that is the Employer (cl 2.25.5). In Walter Lilly [125], on the older JCT form, the review applies irrespective of whether notices and the particulars have been provided.

The practical answer to silence is to have someone else decide, by adjudication. NEC4 says in terms that the Adjudicator may review and revise any action or inaction of the Project Manager (W2.3(4) in the January 2019 wording; W2.3(8) after the January 2023 amendments).

Some forms treat silence as an answer. Under NEC4 the Project Manager must respond in time to a notified compensation event. If it does not, and the failure continues for two weeks after the contractor points it out, the event is treated as accepted (cl 61.4). The contractor is then treated as instructed to quote. Under FIDIC 2017, if the Engineer does not determine a Claim in time, it is deemed to have rejected it (3.7.3).

A certifier's decision binds the parties until someone challenges it. Then an adjudicator, arbitrator or court can open it up and put its own decision in its place. The reasons are the ones already met. The certifier is the employer's agent, and it decides fast. Lord Hoffmann added a third reason in Beaufort: a certificate may have been given when the architect's knowledge of the work, or of the effect of outside causes, was incomplete. Making it conclusive could cause injustice. So interim decisions have only a provisional validity, and a court should require very clear words before reading a contract to make them final (Beaufort, 276).

Three bodies can do the reopening. The first is the court. The Court of Appeal had held in Crouch (1984) that only an arbitrator could open up an architect's certificates, and Beaufort overruled it. The second is the adjudicator. A party to a construction contract has a statutory right to refer a dispute arising under it to adjudication (s.108(1)). The Scheme for Construction Contracts applies where the contract's own procedure falls short (s.108(5)). Under it the adjudicator may open up, revise and review any decision taken or any certificate given, unless the contract states that it is final and conclusive (para 20(a)). The adjudicator's decision binds until the dispute is finally determined (s.108(3)).

The third is the arbitrator, where the contract provides for arbitration. JCT DB 2016 gives the arbitrator power to open up, review and revise any decision, subject to the Final Statement rules in clause 1.8 (cl 9.5).

Adjudication is fast, and accepts the cost of speed. The Court of Appeal said in Carillion v Devonport (2005) that the need to have the "right" answer has been subordinated to the need to have an answer quickly. The certifier's duty runs the other way: it must try to get the answer right. Chapter 15 covers adjudication.

What does the reviewer actually do? It does not defer to the certifier, and it answers the same question the certifier had to answer. That is the lesson of Mace v Baltic (TCC, 2026), the Baltic Exchange case. The contract was on an amended JCT Design and Build Contract 2016 form ([2]), and the extension the adjudicator cut to zero was an interim grant under clause 2.25.1 ([3]-[4]). The contractor, Mace, then made the bold further submission that an interim extension, however incorrect, could not be reviewed by an adjudicator or a court at all ([47]). Counsel for the employer answered that the employer would then be eternally saddled with an erroneous extension ([48]).

The judge, Adrian Williamson KC sitting as a deputy High Court judge, rejected the contractor's submission. The adjudicator can open up, revise and review the extension. But in doing so he must carry out the task the clause requires: a prospective assessment in response to the notice and particulars ([50]). He has to travel back to the time at which they were submitted, and ignore what has happened since ([51]).

The reasoning follows from the contract. The adjudicator has power to replace the certifier's decision, not to rewrite the clause. Clause 2.25.1 asked for a forecast made on the contractor's notice. An adjudicator who used hindsight would be answering a question the clause did not ask at that stage. The contract does ask a hindsight question, but later: at the end-of-job review after practical completion.

Mace needs careful weighing. It is a first-instance decision of a deputy judge, who called the point somewhat novel ([43]), and no later judgment had cited it by September 2026. It also has to sit beside Walter Lilly. There Akenhead J said that a court or arbitrator reviewing what extensions were due has the advantage of knowing what actually happened ([362]), by analogy with the architect's end-of-job review. The two fit if the time frame follows the decision under review: a forecast decision is reviewed as a forecast, and the final review with hindsight. That reconciliation is my reading; Mace did not discuss [362]. Chapter 6 takes the argument further.

Some decisions can move only one way, and some become final when a deadline passes. Both reward the party that acts early.

Under JCT DB 2016 the Employer may review the Completion Date once it has passed, and must do so no later than 12 weeks after practical completion (cl 2.25.5). On that review it can do one of three things. It can fix a later date, whether on reviewing an earlier decision or otherwise, and whether or not the event was notified (cl 2.25.5.1). It can fix an earlier date, but only having regard to any instructions for Relevant Omissions (cl 2.25.5.2). A Relevant Omission is an instruction taking work out of the contract. Or it can confirm the date already fixed (cl 2.25.5.3). It cannot bring the date back because the delay turned out smaller than forecast.

In Mace the judge accepted two submissions as orthodox ([45], [47]). The interim exercise is prospective. And the Employer is then fixed with this extension of time, even at the end-of-job review, unless there have been Relevant Omissions. The textbook passage cited to him puts the consequence directly. An underestimate can be corrected on the review at completion, but overestimates cannot be corrected (Keating, as quoted in Mace [46]). The same passage also suggests that a tribunal looking at extensions long after the events would find it artificial to ignore entirely what in fact happened. That sits uneasily with the judge's ruling that the adjudicator must ignore it ([51]).

The design favours certainty: everyone plans the rest of the job against the interim date, and hindsight at the end would undo that. The employer's protection lies elsewhere. It can take a generous decision to adjudication, as in Mace. And a certifier without the information can hold back, which is why the Protocol expects the minimum.

The model project shows the effect in numbers. It is invented and illustrative: thirteen activities, planned finish week 34, contract completion week 36. By week 18 the roof design information is known to be 4 weeks late; assume that lateness is at the employer's risk. On the programme current in week 18 the job will now finish in week 37, a week beyond the completion date. A certifier deciding then would fix a new Completion Date of week 37.

The contractor then puts more labour on the roofing, wins 2 weeks back and finishes in week 35. With hindsight the job finished inside the original date. But on the JCT review the Employer cannot bring week 37 back to week 36, because nothing was omitted. Here nothing turns on it. Had the contractor's own later problems pushed completion to week 37, it would have owed no liquidated damages at all.

FIDIC and NEC have their own one-way rules. The 2017 Red Book (first printing) tells the Engineer, when reviewing its earlier determinations, that it may increase, but shall not decrease, the total EOT (8.5). Under NEC4 the assessment of an implemented compensation event is not revised, except as the conditions of contract state (cl 66.3).

Finality by lapse of time is the sharper trap. The Scheme does not let an adjudicator reopen a decision the contract states to be final and conclusive (para 20(a)), and each form has its own route to finality. Under JCT DB 2016 the Final Statement is conclusive evidence, from the due date for final payment, that all and only such extensions of time, if any, as are due have been given (cl 1.8.1.2). There are exceptions. Conclusiveness does not arise to the extent that a party disputes the statement by notice before that date, or for fraud. And it is suspended for the subject matter of proceedings started before, or within 28 days after, the statement is issued (cl 1.8.2).

FIDIC is quicker. A party dissatisfied with the Engineer's determination must give a Notice of Dissatisfaction within 28 days of receiving it (3.7.5). If neither party does, the determination shall be deemed to have been accepted by both Parties and becomes final and binding. So under FIDIC an extension decision can be beyond challenge in four weeks. Under NEC4 the Adjudicator's decision becomes final and binding if neither party notifies dissatisfaction within the times the contract sets (W2.3(11)).

What the certifier forecasts, and what a tribunal reviewing it may know, is the subject of chapter 6. The notices that start the process are in chapter 4, adjudication is in chapter 15, and chapter 16 sets the forms side by side.