If you are procuring or managing any of the following infrastructure projects, then understanding the NEC 4 contract and its pricing options is essential to understand:

  • Local transport improvements
  • Bridges, structures and tunnels
  • Drainage and flood alleviation
  • Coastal protection
  • Blue-green infrastructure
  • Hard landscaping
  • Town centre improvements
  • Utility infrastructure
  • Pedestrianisation schemes
  • Highways and road maintenance

 

The NEC 4 contract is the Government’s recommended form of contract for public sector works and is widely used across the infrastructure sector by organisations including National Highways, Network Rail and the Environment Agency. Choosing the right option within it could be the difference between a well-managed, collaborative project and one that is exposed to unnecessary cost and risk.

For a broader comparison of NEC 4 against JCT contracts, including how each handles geopolitical risk and supply chain disruption, I’d recommend reading our in-depth guide written by Will Cooper:

Exploring the Key Differences Between JCT and NEC Construction Contracts

 

What is an NEC 4 Contract?

The NEC 4, or New Engineering Contract fourth edition, is a suite of collaborative, flexible contracts published by the Institution of Civil Engineers in 2017. It replaced NEC3 and is now the most widely used contract form for infrastructure delivery in the UK.

Unlike traditional contracts that focus primarily on risk transfer and legal protection, NEC 4 is built around proactive project management, early warning of problems, and collaborative working between client and contractor. All parties are required to act in a spirit of mutual trust and cooperation, with both sides sharing responsibility for identifying and mitigating risk throughout the project lifecycle.

The NEC 4 suite contains a range of contract types to suit different procurement scenarios, but the primary contract used for construction and infrastructure works is the Engineering and Construction Contract (ECC). Within the ECC, clients choose from six main pricing options – A through F – each allocating risk differently between client and contractor. For infrastructure projects, Options A and C are the most commonly used and the most important to understand.

I’m Jordan Rhoda, Key Account Manager for infrastructure, and in this article, we’re going to break down what each option means in practice, how risk is allocated, and how to determine which is the right fit for your next infrastructure scheme.

 

NEC 4 Option A: Priced Contract with Activity Schedule

NEC 4 Option A is a lump-sum, priced contract linked to an activity schedule. The contractor prices each activity on the schedule at the tender stage, and payment is made upon completion of each activity. It is one of the most widely used options across infrastructure, highways, and civil engineering projects.

 

Risk profile

Option A places the majority of financial risk with the contractor. If costs overrun due to inefficiency or poor planning, the contractor absorbs that risk. The client benefits from greater cost certainty from the outset.

 

Best suited to…

Projects where the scope is well defined at the tender stage and the client wants cost certainty. This makes it particularly appropriate for:

  • Highways and road maintenance schemes
  • Hard landscaping and town centre improvements
  • Pedestrianisation schemes
  • Utility infrastructure works
  • Local transport improvements

 

Key considerations

Because payment is only triggered upon completion of an activity, contractors need to structure their activity schedules carefully to manage cash flow.

Clients should ensure the activity schedule is aligned with the programme to avoid disputes over what constitutes a completed activity. Early warnings remain a contractual requirement under Option A — both parties must notify any matter that could affect time, cost or quality as soon as they become aware of it.

 

NEC 4 Option C: Target Contract with Activity Schedule

NEC 4 Option C is a target cost contract with an activity schedule. Rather than a fixed lump sum, the contractor is reimbursed their defined costs plus a fee, measured against a pre-agreed target price. Any difference between the actual cost and the target cost is shared between the client and contractor through a pain/gain share mechanism.

 

Risk profile

Option C shares financial risk between both parties. If the project comes in under the target cost, both parties share the savings. If it overruns, both share the additional cost. This incentivises the contractor to manage costs efficiently while reducing the client’s exposure compared to a fully cost-reimbursable contract.

 

Best suited to…

Larger, more complex infrastructure projects where the scope may not be fully defined at the tender stage, or where innovation and value engineering during delivery are desirable. It is particularly well-suited to:

  • Bridges, structures and tunnels
  • Drainage and flood alleviation schemes
  • Coastal protection works
  • Blue-green infrastructure
  • Major highway improvement schemes

 

Key considerations

Option C requires full open-book transparency on defined costs throughout the project – this demands robust contract administration from both sides. Early contractor involvement (ECI) under Option X22 works particularly well alongside Option C, bringing the contractor’s expertise into the design and planning phase to help establish a realistic target cost. Clients must ensure they have the resources and understanding to administer an open-book contract effectively – do not rely solely on the Project Manager to manage this on your behalf.

 

Option A vs Option C: Which is Right for Your Infrastructure Project?

The choice between Option A and Option C ultimately comes down to two factors: how well defined your scope is at the tender stage, and how much cost risk you are willing to share.

Option A is the right choice when you have a clearly defined scope, want cost certainty, and are procuring relatively straightforward works. Option C is the better fit when complexity, innovation or evolving design requirements mean a fixed price is neither realistic nor fair to either party.

For infrastructure projects in the current climate, where supply chain volatility, material cost fluctuations and geopolitical uncertainty are live risks, Option C’s risk-sharing model is increasingly attractive on larger schemes. The pain/gain mechanism incentivises the contractor to find efficiencies and manage costs collaboratively, rather than building excessive risk contingency into a fixed price.

That said, Option C is not a blank cheque – the open-book requirements and active contract management it demands mean it is only appropriate where both client and contractor teams have the experience and resource to administer it properly.

 

Choosing the Right NEC 4 Option for Your Project

There is no universal answer to which NEC 4 option is best; it depends on the nature of your project, your organisation’s capacity, and the risk profile you are working within. What is consistent across all NEC 4 options is the requirement for proactive management, early warnings, and genuine collaboration between all parties.

At Procure Partnerships, our infrastructure specialists work with public sector clients across all of the project types outlined above. Contact me today at jordan@procurepartnerships.co.uk or call me directly on 07507 295782. Whether you are at the early stages of procurement planning or need support selecting and administering the right NEC 4 option for your next scheme, we can provide the expertise to help you proceed with confidence.

 

Further Reading & Sources

The following resources provide additional detail on NEC 4 contracts and infrastructure procurement:

  • NEC Official Website
    • NEC4 ECC Option Details – detailed breakdown of all six pricing options, including Option A and Option C
    • Institution of Civil Engineers – NEC4 Contract Overview – an overview of NEC4’s key features, contract options and practical advantages from the governing body
  • RICS – NEC Principles and NEC4 Engineering