Mace Construct Ltd v Baltic Investment Holdings Ltd [2026] EWHC 976 (TCC)
A significant recent decision of the Technology and Construction Court has considered whether an adjudicator may open up, review and reduce an extension of time granted during the course of the works under a JCT contract. In Mace Construct Ltd v Baltic Investment Holdings Ltd [2026] EWHC 976 (TCC), the Court confirmed that a contemporaneous extension of time is capable of being reviewed by an adjudicator, arbitrator or court. However, the reviewing decision-maker cannot simply use hindsight to determine what delay ultimately occurred. The assessment must remain prospective.
The adjudicator must effectively travel back to the time when the original extension of time assessment should have been undertaken, “stand in the shoes” of the Employer’s Agent and decide what extension was fair and reasonable based upon the information available at that time. Events occurring afterwards must be disregarded. That distinction is important because the question is not necessarily what delay the Relevant Event ultimately caused, but what delay the Relevant Event was reasonably expected to cause when the Contractor’s application was made and the assessment was due.
The judgment is likely to have substantial consequences for the preparation, assessment and adjudication of extension of time claims under the JCT forms. It may also have wider relevance to other forms of contract which require extensions of time to be assessed while the works remain in progress.
Prospective and retrospective delay analysis
Construction disputes frequently require delay to be analysed. Contractors may seek extensions of time, loss and expense or prolongation costs, while employers may seek to deduct liquidated damages or pursue damages arising from alleged delay. Delay experts are commonly instructed to identify the causes and effects of delay, but there is no single delay-analysis methodology that is appropriate in every case.
The correct approach depends upon the contractual question that must be answered, the wording of the relevant contractual provisions, the timing of the assessment, the quality of the contemporaneous records and the factual characteristics of the project. Delay analysis should therefore begin with the contract and the issue to be determined, rather than with an expert’s preferred methodology.
At a broad level, delay analysis can be divided into prospective and retrospective approaches. A prospective analysis considers the likely effect of an event at the time it occurred, or at the time when its consequences were being assessed. Time-impact and impacted as-planned analyses are commonly associated with prospective assessment, although the label attached to the methodology is less important than whether the analysis answers the question required by the contract.
A retrospective analysis considers the progress of the works with the benefit of hindsight. It examines what actually happened and seeks to determine whether an event ultimately caused delay to completion when viewed against the project’s progress as a whole. The distinction is not merely technical because a prospective assessment and a retrospective assessment may produce different answers.
An event may reasonably appear likely to delay completion when assessed contemporaneously, but subsequent mitigation, acceleration, resequencing or changes to the critical path may mean that the predicted delay never materialises. Conversely, an event which initially appears relatively insignificant may ultimately have a much greater effect than was reasonably foreseeable at the time.
Is hindsight always preferable?
It may appear instinctively attractive to determine a dispute using all the information ultimately available. The frequently cited decision in Bwllfa and Merthyr Dare Steam Collieries (1891) Ltd v Pontypridd Waterworks Co [1903] AC 426 reflects that approach. Lord Macnaghten famously questioned why an arbitrator should estimate when the answer could be calculated with the benefit of subsequent facts.
That reasoning is particularly influential in claims for damages. Where the court is assessing the loss caused by a breach of contract, subsequent events may provide the best evidence of what loss was actually sustained. A similar approach was taken in Northern Ireland Housing Executive v Healthy Buildings (Ireland) Ltd [2017] NIQB 43, where an attempt to confine the assessment of compensation under an NEC contract to a prospective analysis was unsuccessful.
In Fluor Ltd v Shanghai Zhenhua Heavy Industries Ltd [2018] EWHC 1 (TCC), the Court also concluded that some form of retrospective analysis was required when determining delay arising from defective work and the resulting breach of contract. However, the Court distinguished such claims from the assessment of an extension of time, where a prospective exercise may be contractually required.
The legal and contractual question must therefore be identified before the delay methodology is selected. A methodology should not be chosen merely because it is familiar, convenient or preferred by the expert. A technically sophisticated analysis may still be of limited assistance if it answers the wrong contractual question.
The JCT extension of time machinery
The JCT Design and Build Contract requires the Contractor to notify the Employer of delay caused by a Relevant Event and to provide particulars of its expected effects. Where completion is likely to be delayed beyond the Completion Date, the Employer must determine an extension of time that is fair and reasonable.
The wording is inherently prospective. The Employer is required to consider whether completion “is likely” to be delayed and must therefore make the assessment by reference to the circumstances and information available at that point. It is an estimate of the anticipated effect of the event, rather than a retrospective determination of what ultimately occurred.
The JCT machinery also provides for a further review after Practical Completion. This operates as a final sweep-up exercise during which the overall extension of time position may be reconsidered. Importantly, however, the final review ordinarily cannot reduce the Completion Date below a date previously fixed through an earlier extension of time, except insofar as an adjustment results from a Relevant Omission.
This creates an important contractual distinction between a contemporaneous extension of time assessed while the works are progressing and the final extension of time review undertaken after Practical Completion. The contemporaneous decision necessarily involves an estimate of what is likely to happen, whereas the final review takes place with considerably more information available. Nevertheless, the contractual restrictions upon reducing a previously granted extension remain important.
The Baltic Exchange project
The dispute arose from the refurbishment of the former Baltic Exchange Building at 38 St Mary Axe in London. Mace Construct Ltd was engaged under an amended JCT Design and Build Contract 2016. During the works, the Employer’s Agent granted Mace an extension of time totalling seven weeks and five days.
The extension related principally to design changes and the need to obtain further approvals and listed-building consents. Baltic subsequently concluded that the extension granted by the Employer’s Agent had been excessive and referred the issue to adjudication.
The adjudicator opened up and reviewed the Employer’s Agent’s assessment. He concluded that Mace had no entitlement to the extension and reduced the award to zero. The dispute subsequently came before the TCC by way of Part 8 proceedings.
Among the issues to be determined was whether an adjudicator or the Court had power to review and reduce a contemporaneous extension of time. This was particularly important because the JCT provisions restricted the Employer’s ability to reduce an earlier extension during the final extension of time review.
Could the adjudicator open up the extension of time?
Mace argued that the contemporaneous extension of time could not properly be reviewed because a later decision-maker could never recreate the prospective assessment required by the contract. The adjudicator or court would inevitably know how the works had subsequently progressed and whether the predicted delay had actually materialised.
The Court rejected that argument. Paragraph 20(a) of the Scheme for Construction Contracts gives an adjudicator power to open up, revise and review decisions taken or certificates issued under the contract, unless the contract provides otherwise. The Employer’s Agent’s extension of time assessment was therefore capable of being reviewed in adjudication.
However, the adjudicator’s jurisdiction to review the assessment did not alter the nature of the contractual exercise. If the Employer’s Agent was required to undertake a prospective assessment, the adjudicator was required to undertake the same prospective assessment when reviewing the decision.
An adjudicator may therefore open up and revise a contemporaneous extension of time, but must apply the contractual test which the Employer’s Agent should originally have applied. The adjudicator is entitled to reach a fresh decision on the merits, but not to substitute a retrospective exercise for the prospective exercise required by the contract.
Standing in the shoes of the Employer’s Agent
The most important aspect of the judgment is the Court’s explanation of how the review must be conducted. The adjudicator must stand in the shoes of the Employer’s Agent, return to the time when the Contractor’s notice and supporting particulars were submitted, consider the information then available and assess what delay was then likely to occur.
The adjudicator must determine what extension was fair and reasonable at that time. Subsequent events and the knowledge gained from them must be disregarded. The adjudicator is not being asked to decide, with hindsight, whether the event ultimately delayed completion. The adjudicator is instead determining whether the Employer’s Agent’s prospective assessment was correct when judged against the information and circumstances existing at the relevant time.
The fact that the adjudication takes place months or years later does not convert the contractual question into a retrospective one. The date at which the original assessment ought to have been made therefore becomes a central part of the analysis.
This requires a careful separation between the adjudicator’s present-day task of deciding the dispute and the historic date by reference to which the contractual assessment must be made. That separation may be easier to state than to apply. Once the eventual outcome of the project is known, consciously disregarding that knowledge may prove difficult. Nevertheless, the Court has made clear that hindsight must not influence a strictly prospective contractual assessment.
The role of the delay expert
The judgment has important consequences for delay experts. Experts are commonly instructed after completion and are often provided with the complete project record. They may know the actual date of Practical Completion, the eventual sequence of the works, the final critical path and whether a predicted delay did or did not materialise.
In a dispute concerning the correctness of a contemporaneous JCT extension of time, much of that information may be irrelevant to the contractual question. The expert may instead be required to reconstruct the position existing at a particular historic date and exclude later information which was not available to the original decision-maker.
The expert may need to identify the accepted or current programme at the assessment date, the progress achieved by that date, the activities then regarded as critical or potentially critical and the notices and particulars provided by the Contractor. The expert should also consider the information available to the Employer’s Agent, the assumptions reasonably capable of being made and the mitigation or resequencing then proposed.
An expert who relies upon later programmes, subsequently discovered information or the actual progress achieved after the assessment date may be answering the wrong question. The judgment therefore reinforces a fundamental point: delay analysis must follow the contract and the issue referred for determination. The methodology should not dictate the legal question.
The evidential challenge
A prospective reconstruction undertaken years after the relevant event may present considerable evidential difficulties. The quality of contemporaneous records is therefore likely to become critical. Updated programmes, progress reports, meeting minutes, design trackers, correspondence and contemporaneous assessments may provide the most reliable means of establishing what could reasonably have been known at the time.
Parties should preserve successive versions of programmes, reports and assessments produced throughout the works. It may not be sufficient to retain only the final programme or the final account records. Historic programme updates and contemporaneous records may be essential if a later adjudicator or court is required to reconstruct the position as it stood at a particular date.
The reviewing decision-maker may also need to distinguish between information that was actually available, information that ought reasonably to have been available, information created later but purporting to describe the earlier position and information revealing what ultimately occurred. The latter may have to be excluded even though it would otherwise appear highly persuasive.
Can subsequent events provide a reality check?
In Walter Lilly & Co Ltd v Mackay [2012] EWHC 1773 (TCC), the Court considered prospective delay analysis but was also able to compare its results against subsequent events. The later facts effectively provided a reality check.
The reasoning in Mace v Baltic appears considerably stricter when dealing with the review of a contemporaneous extension of time. Where the contractual assessment must be made prospectively, later events should not be used to correct, confirm or test the result. Doing so risks allowing hindsight to affect the very assessment which the Court has said must be undertaken as at the earlier date.
This may produce a result that appears inconsistent with what ultimately happened on site, but that does not necessarily make the result wrong. A contemporaneous extension of time is an assessment of likely future delay. It is not necessarily a final determination of the delay ultimately experienced.
Certainty or accuracy?
The judgment exposes a tension between contractual certainty and factual accuracy. A retrospective analysis may provide a more accurate account of what ultimately delayed completion. However, the JCT machinery is intended to permit decisions to be made during the works, and those decisions affect the Completion Date, the Contractor’s potential liability for liquidated damages and the parties’ ongoing commercial positions.
A prospective assessment supports the proper operation of that machinery because contractors and employers need to know where they stand while the project remains underway. The cost of that certainty is that a contemporaneous extension may later appear generous or inadequate when judged against what eventually happened.
Under the JCT provisions, an extension properly granted on a prospective basis may remain effective even where subsequent events demonstrate that the predicted delay did not fully materialise. That is not necessarily an error in the contractual process. It may be the intended consequence of the contractual bargain.
Practical implications for contractors
For contractors, the decision reinforces the value of submitting properly evidenced extension of time applications during the course of the works. A contractor should not assume that an extension of time can be dealt with adequately as part of a final account submission after completion.
A contemporaneous application should identify the Relevant Event relied upon, explain when the event occurred and identify which activities were affected. It should state the status of the programme immediately before the event, explain why the affected activities were critical or likely to become critical and set out the anticipated effect upon completion.
The assumptions underlying the assessment should be stated clearly, together with the steps being taken to avoid or reduce the anticipated delay. The application should provide the Employer or Employer’s Agent with sufficient information to undertake a meaningful prospective assessment.
Where the Employer or Employer’s Agent fails to make a proper assessment, the contractor may consider referring the matter to adjudication while the works remain ongoing. Obtaining a contemporaneous extension may provide significant protection against liquidated damages and, subject to the precise contractual amendments, may not subsequently be capable of being reduced merely because hindsight shows that the event had a lesser effect than originally anticipated.
However, the decision does not remove the need for contractual compliance. Contractors must continue to pay close attention to notice requirements, timescales and the obligation to provide adequate particulars.
Practical implications for employers
Employers and Employer’s Agents should treat contemporaneous extension of time assessments with considerable care. An extension granted during the works may have lasting consequences and may not be capable of being reduced during the final review merely because subsequent events show that the original forecast was too generous.
The assessment should identify the relevant contractual provision, record the information considered and state the effective assessment date. It should identify the programme relied upon, explain the anticipated effect of the Relevant Event and address concurrency, mitigation and resequencing where relevant.
Clear reasons should be given for the period awarded. The decision should not simply state the number of days granted. A reasoned contemporaneous assessment will be far easier to defend if it is subsequently opened up in adjudication.
Employers should also ensure that applications are considered promptly. An assessment undertaken long after the contractual decision date may already have been influenced by hindsight and may no longer reflect the prospective exercise required by the contract.
Notices and conditions precedent
The judgment may encourage employers to place greater emphasis upon compliance with contractual notice provisions. If a contractor seeks the benefit of a strictly prospective assessment, the employer may argue that the contractor must also comply strictly with the contractual machinery which triggers that assessment.
Whether a particular notice provision operates as a condition precedent will depend upon the wording of the contract. Clear language is ordinarily required before a failure to give notice will extinguish an otherwise valid entitlement.
Nevertheless, contractors should not assume that general awareness of a delaying event will be sufficient. Notices should be issued in accordance with the contract, within the required timescale and with sufficient particulars to permit a meaningful prospective assessment.
Implications for adjudicators
For adjudicators like me, the judgment requires careful identification of the dispute and the contractual question. An adjudicator asked to review a contemporaneous extension of time should identify the date at which the original assessment should have been made, the contractual test applicable at that date and the information provided with the Contractor’s application.
The adjudicator should also identify the other information properly available to the Employer’s Agent, the programme against which likely delay is to be measured and which subsequent facts must be disregarded. The parties should be given a fair opportunity to address the prospective basis of assessment.
A decision based upon what ultimately occurred may answer a materially different question from the one arising under the contract. Depending upon the circumstances, that could amount to an error of law, although an error of law falling within the adjudicator’s jurisdiction would not ordinarily prevent enforcement.
Contemporaneous and final extensions of time
The decision may generate further disputes concerning the relationship between individual contemporaneous awards and the final extension of time review. One issue which remains comparatively undeveloped in the authorities is whether the restriction upon reducing an earlier extension protects each individual award for each Relevant Event, or whether it protects only the overall Completion Date resulting from the cumulative extension of time assessment.
This distinction may become important where an Employer’s Agent concludes during the final review that one event was previously overvalued but another event justifies an additional extension. The judgment provides important guidance on the review of the contemporaneous decision itself, but questions remain about the precise operation of the contractual floor created by previously awarded extensions.
The answer is likely to depend upon the wording of the particular contract and any amendments made to the standard JCT provisions.
A warning against methodology-led analysis
One of the wider lessons from the decision is that delay analysis should not begin with a preferred methodology. It should begin with the contractual and legal question.
An expert may carry out a technically sophisticated retrospective analysis and accurately establish what ultimately occurred. However, that evidence may be of limited assistance if the contract requires the decision-maker to assess what was likely to occur at an earlier point in time.
Equally, a prospective methodology may be inappropriate where the issue is the actual loss caused by a breach of contract and the tribunal is entitled to consider the complete factual history. The analysis must be designed to answer the question which the contract and the dispute require to be answered.
Conclusion
Mace Construct Ltd v Baltic Investment Holdings Ltd provides important clarification concerning the review of contemporaneous extensions of time under the JCT form. An extension of time granted by an Employer’s Agent is not necessarily immune from review. An adjudicator, arbitrator or court may open up, revise and review the assessment.
However, the reviewing decision-maker must apply the same contractual test as the original decision-maker. Where the contract required a prospective assessment, the adjudicator must stand in the shoes of the Employer’s Agent, return to the relevant assessment date and determine what delay was then reasonably likely to occur. Subsequent events must be ignored.
For contractors, the judgment strengthens the importance of properly prepared contemporaneous applications supported by programmes and reliable records. For employers and Employer’s Agents, it highlights the potential permanence of an extension granted during the works and the need for careful, reasoned and timely assessments.
For adjudicators and delay experts, the decision serves as a reminder that hindsight is not always permissible. The correct analytical methodology is ultimately dictated by the contract. The most accurate account of what eventually happened may not always answer the contractual question which has to be decided.