Parties

The NEC Parties definition is the shortest in the list: the Parties are the Client and the Contractor (the Employer and the Contractor in NEC3). The Project Manager and the Supervisor aren't Parties, even though they do most of the talking. Plenty of bad assumptions about authority come from missing that difference.

The definition is in clause 11.2 (item 11 in NEC3 ECC). A subcontract's two Parties are the Contractor and the Subcontractor, and the Client isn't one. This page is part of the NEC definitions glossary, and the guide to NEC roles covers what each person does.

Who does what

Role	A Party?	What that means in practice
Client	Yes	Pays, provides what the Scope says it will, and can agree to change the contract
Contractor	Yes	Provides the works, and can agree to change the contract
Project Manager	No	Acts under the powers the contract gives, as appointed by the Client
Supervisor	No	Tests, inspects and handles Defects as the contract says
Adjudicator	No	Decides disputes referred under a separate appointment
Subcontractor	No	Bound by its own contract with the Contractor

Where the distinction matters

• Changing the contract. Clause 12.3 says that, where the conditions don't otherwise provide for it, a change needs agreement, written confirmation and signature by the Parties.
• Entire agreement. Clause 12.4 treats the contract as the whole agreement between the Parties, so side discussions don't simply carry over.
• Prevention and other tests. Clause 19 asks whether neither Party could have prevented an event, so the actions of the two named organisations are what's tested.
• Disputes. Under the dispute Options, referrals are made by a Party.
• Ambiguity. When an instruction resolves an ambiguity in the Scope, assessment favours the Party that didn't provide the Scope (63.10; 63.8 in NEC3).
• Behaviour. Clause 10 covers the Project Manager and Supervisor as well as the Parties in NEC3 ECC, because they have to act as the contract says too. See clause 10.

A worked example

A fictional depot scheme. The Contractor's commercial manager and the Project Manager agree by email to shorten the assessment interval from four weeks to two, to help the Contractor's cash flow. The Project Manager then certifies on that basis for three months.

• The contract's interval is set in the Contract Data, and no clause gives the Project Manager power to change it.
• Under 12.3, the change has no effect unless both Parties sign. Neither the email nor the practice counts as that.
• When the Client's finance team finds out, it can query the extra payments and the earlier due dates.
• The fix is simple: a short signed variation between Client and Contractor, setting the new interval from a stated date.

Whether months of conduct would change the legal position is a question for a lawyer. It's a poor basis for running a contract either way.

What people get wrong

• Assuming a Project Manager from the Client's staff speaks as the Client. Wearing that hat, they act under the contract. A concession outside those powers isn't the Client's agreement unless the Client gives it.
• Going over the Project Manager's head. Client and Contractor can talk, but instructions under the contract still come through the named role. A direct request from a Client's director is not an instruction.
• Forgetting third parties. Rights for people outside the contract, for example future tenants, depend on the law and on options such as Option Y(UK)3 and X8.
• Confusing the subcontract's Parties. A Subcontractor generally has no direct route to the Client under the subcontract. Their claim runs against the Contractor.
• Treating a Z clause as changing only the Parties. Z clauses often give the Client approval rights over Project Manager decisions. Read them, because they alter how this all works.

Related guides

• NEC Definitions: A Glossary of Key Terms
• People
• Plant and Materials
• Prices
• Key Date
• Others

This guide is general information in our own words, not legal advice. Your contract and its Contract Data always govern. NEC, NEC3 and NEC4 are trade marks of Thomas Telford Ltd; Contract Status is not affiliated with or endorsed by NEC.