JCT and NEC are two of the most widely used families of standard-form construction contracts in the UK. RIBA’s Construction Contracts and Law Report 2022 found that 59% of respondents said JCT contracts were the contracts their organisation used most often, compared with 13% for NEC contracts. However, the difference between JCT and NEC goes considerably further than terminology or contract structure. Each takes a different approach to allocating risk, managing change and administering a project.
JCT contracts traditionally establish where risks and responsibilities sit at the outset, providing a familiar contractual framework that is particularly prevalent in building projects. NEC contracts place greater emphasis on actively managing risks as the project progresses, using mechanisms such as early warnings, an accepted programme and compensation events.
Those differences affect the way a project needs to be managed. A team accustomed to administering a traditional JCT contract cannot assume the same processes will work under NEC. NEC generally demands more active contract management, timely decision-making and greater involvement from the employer’s project team.
Understanding these practical differences is therefore an important part of choosing the appropriate contract. The question is not simply which form best allocates the project’s risks, but whether the parties have the resources and experience to operate it effectively.
Summary
- Origins and Purpose of JCT and NEC
- Approach to Risk
- Roles and Administration
- The Programme
- Time, Cost and Compensation Events
- Payment Options
- Language and Dispute Resolution
- Amendments and Bespoke Drafting
- Which Contract is Right for Your Project?
Origins and Purpose of JCT and NEC
The Joint Contracts Tribunal (JCT) has produced standard forms of construction contract since 1931 and has become particularly established within the UK building sector. Its suite includes contracts suited to different procurement approaches, including traditional procurement and design and build.
A traditional JCT contract generally establishes the parties’ respective responsibilities and allocates contractual risks at the outset. This can provide greater certainty where the scope is well defined and the employer wants risks allocated clearly between the parties.
The New Engineering Contract (NEC) emerged much later and was developed with a different purpose. Its contracts were expressly designed to promote good project management, using clear processes through which the parties identify and deal with risks and changes while work is underway. The NEC suite has consequently become particularly prominent on major engineering, infrastructure and public-sector projects.
The distinction is less clear-cut than it once was. JCT 2024 has strengthened its emphasis on collaborative working, while the introduction of the JCT Target Cost Contract 2024 has expanded the suite beyond its more traditional approaches to pricing and risk.
Nevertheless, an important difference remains. JCT principally provides a contractual framework within which the parties deliver the agreed works and deal with events as they arise. NEC places project management processes much closer to the centre of the contract itself. That difference in philosophy becomes particularly apparent when we look at how the two forms deal with risk.
Approach to Risk
One of the clearest differences between JCT and NEC is how risk is handled. JCT primarily allocates risk between the parties through the contract, while NEC combines risk allocation with an active process for identifying and managing emerging risks during the project.
Under NEC4, both the Contractor and Project Manager must give an early warning of matters that could increase cost, delay Completion or impair performance. These are recorded in the Early Warning Register and discussed so that the parties can consider how the risk might be avoided or its effects reduced. The process is intended to bring potential problems into the open before their consequences become fixed.
JCT does not contain an equivalent early warning process or risk register. Instead, the contract contains more provisions determining which party bears particular risks and what entitlement follows when specified events occur.
This creates an important practical distinction. NEC requires the project team to monitor and communicate risk continually, rather than waiting to establish contractual entitlement once an event has occurred. However, that advantage depends on the parties having the resources and discipline to use the early warning process properly. A collaborative contract cannot compensate for passive contract management.
Roles and Administration
JCT and NEC also place different demands on the people administering the contract. JCT typically uses a Contract Administrator, or an Employer’s Agent under Design and Build, while NEC gives the Project Manager a more active role in managing the contract and project.
Under JCT, the administrator oversees contractual procedures, including payment and other decisions required under the contract. The role is comparatively limited and can be more reactive, dealing with issues as they arise.
The NEC Project Manager has broader, ongoing responsibilities. This includes managing processes such as early warnings, programme acceptance and compensation events, with decisions often required within defined timescales. NEC experience and sufficient resources are therefore particularly important.
In practice, this affects what the employer needs from its project team. NEC demands regular engagement and timely decision-making from both parties throughout delivery. Without that management capacity, the procedures intended to encourage cooperation and resolve issues early can themselves become a source of contractual difficulty.
The Programme
The programme has a very different contractual significance under JCT and NEC. Under JCT, the contractor submits a master programme, but under NEC the programme is a central tool for managing progress, risk and change throughout the project.
A JCT master programme is not itself a contractual document and there is no general requirement to keep updating it throughout the works. This reduces the administrative burden, but also means the programme plays a more limited role in contract management.
NEC requires a more detailed programme that is regularly updated and accepted by the Project Manager. It includes information such as float and time risk allowances and provides the basis for assessing compensation events, monitoring progress and identifying potential delays early.
The benefit is greater visibility of where a project is heading. However, that depends on maintaining an accurate, accepted programme. Teams choosing NEC therefore need the capability to treat programme management as an ongoing contractual obligation, rather than simply a project-planning exercise.
Time, Cost and Compensation Events
JCT and NEC take significantly different approaches to dealing with events that affect the cost and completion of a project. JCT generally considers time and money separately, while NEC brings their effects together through its compensation event procedure. This affects both how entitlement is established and when the financial and programme consequences are assessed.
Under JCT, Relevant Events may entitle the contractor to an extension of time, while a separate, shorter list of Relevant Matters may provide entitlement to loss and expense. An extension of time therefore does not automatically mean the contractor can recover the additional costs associated with that delay. These effects are generally assessed retrospectively, once more is known about what has actually happened.
NEC integrates time and cost through compensation events. NEC4 contains a standard list of compensation events that can entitle the contractor to adjustments to both the Prices and Completion Date. These are generally assessed prospectively, based on the forecast effect of the event, rather than waiting until its full consequences are known.
That approach comes with stricter administration. Where the Contractor is responsible for notifying a compensation event, failure to do so within the required eight-week period can, subject to exceptions, result in loss of entitlement. Failure to give an early warning can also affect how a compensation event is assessed.
What Can Go Wrong with Compensation Events?
NEC’s integrated approach can give both parties earlier visibility of the likely effect of change on time and cost. However, that advantage depends on notifications, quotations, programme updates and responses being made correctly and on time.
This is the practical difference between the two forms. JCT’s separation of time and money can mean claims take longer to resolve and create uncertainty while assessments remain outstanding. NEC aims to resolve those consequences as the project progresses, but places greater administrative demands on the people managing the contract. A team that treats NEC compensation events like retrospective JCT claims risks undermining one of the principal benefits of the NEC approach.
Payment Options
JCT and NEC both offer different approaches to pricing and payment, although they structure those choices differently. JCT provides different contract forms to suit different procurement and pricing arrangements, while the NEC4 Engineering and Construction Contract offers six main pricing options within the same contract structure.
Traditional JCT arrangements commonly use an agreed Contract Sum, with interim payments based on monthly valuations or agreed stage payments. Depending on the chosen JCT form, pricing can involve quantities, approximate quantities, schedules of rates or other mechanisms. Provisional sums can also be included where elements of the work cannot be fully defined when the contract is entered into.
JCT has also expanded its approach with the Target Cost Contract 2024, under which allowable costs are reimbursed and differences against an agreed target cost are shared through a pain/gain mechanism.
Under NEC4, the six main options are:
- A and B: priced contracts, using an activity schedule or bill of quantities respectively
- C and D: target contracts, again using an activity schedule or bill of quantities
- E: cost reimbursable
- F: management contract.
The choice determines how cost risk is distributed and how much ongoing cost management is required. Target-cost and cost-reimbursable arrangements can provide flexibility and transparency but demand stronger cost records and administration from the project team.
Language and Dispute Resolution
JCT and NEC use noticeably different drafting styles, although both provide established routes for resolving disputes. JCT uses more traditional legal drafting, supported by a substantial body of case law, while NEC was deliberately written in plainer language and places greater emphasis on resolving issues during the project.
NEC’s shorter sentences and defined processes are intended to make the contract accessible to the people managing the works. However, plain English should not be mistaken for simplicity. Its procedural requirements and strict timescales still require a thorough understanding of how the contract operates.
JCT’s more conventional legal language can appear less accessible, but its long history means there is considerably more case law to assist with interpretation. In addition, the 2024 edition introduced gender-neutral language and email notices.
Both forms provide for adjudication, with further dispute resolution routes available depending on the contract terms. NEC’s early warning and compensation event processes are also intended to address problems before they develop into formal disputes. The practical advantage depends, once again, on those processes being actively and correctly administered.
Amendments and Bespoke Drafting
Standard forms are frequently amended to reflect project-specific requirements, but amendments can materially alter the risk allocation and management processes that influenced the choice of contract in the first place.
Under JCT, bespoke provisions are typically introduced through a Schedule of Amendments. NEC uses Z clauses, which allow additional conditions to be incorporated into the contract.
Amendments may be necessary to address matters such as project-specific risks, funder requirements or the parties’ commercial positions. However, even apparently minor changes can have unintended consequences elsewhere in the contract.
This is particularly important under NEC, where different processes are designed to operate together. Extensive Z clauses can alter risk allocation, introduce conflicting procedures or undermine the collaborative management approach the standard form is intended to support. Similarly, heavily amending a JCT contract can shift risks significantly from the standard position.
The final contract should therefore be reviewed as a whole. The fact that a project starts with a familiar JCT or NEC form does not necessarily mean the agreement that is signed retains the characteristics normally associated with that form.
Which Contract is Right for Your Project?
There is no universal answer to whether JCT or NEC is the better choice. The appropriate contract depends on the project’s complexity and risk profile, the procurement and pricing approach, and the experience and resources available to administer it effectively.
JCT may suit projects where the scope is relatively well defined and the parties want risks clearly allocated from the outset. Its familiarity within the building sector can also be important where contractors, consultants and funders are accustomed to its structure. Funders may particularly favour the clearer transfer of risk available under forms such as JCT Design and Build.
NEC can be well suited to complex infrastructure and public-sector projects where change is more likely and the employer wants risks, programme and cost actively managed throughout delivery. Its flexibility can be valuable, but the employer must have an experienced team capable of meeting the contract’s ongoing administrative requirements.
Contract choice should therefore consider management capability as well as contractual risk. Selecting NEC without the resources to operate its processes effectively can undermine its benefits, while imposing its additional management requirements on a straightforward project may offer limited value. Equally, JCT’s familiarity should not be the sole reason for selecting it where the project would benefit from more proactive risk management.
Choosing the Right Contract from the Start
The difference between JCT and NEC extends beyond the wording of the contract. Each establishes different expectations for how risk, programme, cost and change will be managed throughout the project.
JCT can provide a familiar framework with risks more clearly allocated at the outset, while NEC offers processes designed to identify and manage issues as they emerge. Neither approach is inherently better. The right choice depends on the project and, importantly, whether the parties have the experience, systems and resources to administer the chosen contract properly.
The consequences of getting that decision wrong may only become apparent once the project is underway, when contractual processes are missed or the agreed risk allocation is tested.
Witan’s Construction Law team advises employers, contractors and other construction businesses on selecting, negotiating and amending JCT and NEC contracts. Taking advice before signing can help ensure the contract reflects both the risks of the project and the way it will actually be managed.
If you would like advice about construction contracts, contact our team on 0300 303 2071 or complete our online enquiry form to discuss how we can help.
