Nationally Significant Infrastructure Projects: Terms commonly used in the process
Source: gov.uk (2025-11-03)

This list of commonly used terms is intended to assist persons who are affected by an application under the Planning Act 2008 who may be unfamiliar with the language used to describe aspects of the process.

Access required site inspection (commonly abbreviated as ‘ARSI’)

An access required site inspection is a visit to an area of the application site or its surroundings by the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) on land that is not publicly accessible. This type of site inspection will normally require the landowner or another interest in the land (#interest-in-land) to attend to grant access to the land and accompany the Examining Authority during the visit. Other interested parties (#interested-party-commonly-abbreviated-as-ip), including the applicant, do not attend.

Accompanied site inspection (commonly abbreviated as ‘ASI’)

An accompanied site inspection is a visit to the application site and its surrounding by the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) which can also be attended by the applicant and other interested parties. It is an opportunity for the Examining Authority to see the area affected by the project (#project) and for interested parties (#interested-party-commonly-abbreviated-as-ip) to point out features. It is not the time for interested parties] to say what they like or don’t like about the project.

Affected person (commonly abbreviated as ‘AP’)

Affected persons are people or organisations who own or have an interest in the land (#interest-in-land) that could be affected by a project (#project). The Applicant (#applicant) can seek powers to acquire land and rights over land from an affected person to enable a project to be built and operated. This is known as compulsory acquisition (#compulsory-acquisition-commonly-abbreviated-as-ca). The applicant can also seek powers to acquire land and rights from an affected person on a temporary basis, known as temporary possession (#temporary-possession-commonly-abbreviated-as-tp).

Applicant

The applicant is the organisation that submits an application (#application) for a development consent order (#development-consent-order-commonly-abbreviated-as-dco) to the Planning Inspectorate.

Application

This refers to the applicant’s application for a development consent order (#development-consent-order-commonly-abbreviated-as-dco). An application consists of a series of documents and plans which are published on the Find a National Infrastructure Project website (https://national-infrastructure-consenting.planninginspectorate.gov.uk/).

Book of Reference (commonly abbreviated as ‘BoR’)

The Book of Reference is a document that the applicant (#applicant) submits with its application (#application) listing all land plots affected by the project (#project) and the details of all persons or organisations with legal interests in those plots. Persons or organisations listed in the Book of Reference are affected persons (#affected-person-commonly-abbreviated-as-ap) and persons or organisation who may be eligible to make a relevant compensation claim (#relevant-compensation-claim).

Compulsory acquisition (commonly abbreviated as ‘CA’)

Compulsory acquisition refers to the legal power the applicant (#applicant) can seek to take ownership of land and rights over land to enable a project (#project) to be built and operated.

Compulsory acquisition hearing (commonly abbreviated as ‘CAH’)

A compulsory acquisition hearing is for the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) to discuss the applicant’s case for requesting compulsory acquisition (#compulsory-acquisition-commonly-abbreviated-as-ca) and temporary possession (#temporary-possession-commonly-abbreviated-as-tp) in their application (#application). It is also an opportunity for the Examining Authority to listen to the views of affected persons. Only affected persons (#affected-person-commonly-abbreviated-as-ap) have the right to ask for a compulsory acquisition hearing to take place.

Change request

After an application (#application) has been accepted by the Planning Inspectorate there may be circumstances when the applicant considers making a change to the project. The applicant (#applicant) will consult people and organisations about the proposed change before they ask the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) to examine it.

Correction order

A correction order to a development consent order (#development-consent-order-commonly-abbreviated-as-dco) is used to fix minor mistakes or errors in the original development consent order that was already approved. Minor mistake or errors may include typographical errors, wrong dates or incorrect references.

Development consent obligation (commonly abbreviated as ‘DCOb’)

A legal agreement between the applicant (#applicant) and a local authority or other interested party (#interested-party-commonly-abbreviated-as-ip) that will set out the planning obligations that are not considered appropriate to be secured as requirements (#development-consent-order-requirement) to the development consent order (#development-consent-order-commonly-abbreviated-as-dco). A development consent obligation is similar to a section 106 agreement under the Town and Country Planning Act 1990.

Development consent order (commonly abbreviated as ‘DCO’)

A statutory order which provides consent for the project (#project) and means that a range of other consents, such as planning permission and listed building consent, will not be required. A development consent order can also include powers authorising the compulsory acquisition (#compulsory-acquisition-commonly-abbreviated-as-ca) and temporary possession (#temporary-possession-commonly-abbreviated-as-tp) of land and rights over land which is the subject of an application. A draft development consent order is submitted by the applicant as part of its application.

Development consent order requirement

A requirement under the development consent order (#development-consent-order-commonly-abbreviated-as-dco) which is proposed to control the construction, operation and maintenance of the development if it is consented. Requirements are similar to planning conditions under the Town and Country Planning Act 1990.

Environmental impact assessment (commonly abbreviated as ‘EIA’)

A process, undertaken by the applicant (#applicant), of identifying and assessing the significant effects likely to arise from a project (#project). It requires consideration of the likely changes to the environment, where these arise because of the project, through comparison with existing and future conditions and describing any mitigation measures which are required.

Environmental statement (commonly abbreviated as ‘ES’)

A report, prepared by the applicant (#applicant), in which the process and results of the environment impact assessment (#environmental-impact-assessment-commonly-abbreviated-as-eia) are documented. The environmental statement is submitted by the applicant as part of the application (#application).

Examination

This is the stage where the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) examines the application (#application). It will:
- ask written questions and oral questions at hearings (#hearing)
- invite comments in writing and at hearings (#hearing)
- visit the area where the project (#project) is proposed to be built and operated
- gather information and test evidence
- make procedural decisions (#procedural-decision) on how the examination will proceed as needed
Examining Authority (commonly abbreviated as ‘ExA’)

An Examining Authority is appointed by the Planning Inspectorate on behalf of the Secretary of State to carry out the examination (#examination) of the application (#application). The Examining Authority is made up of either a single independent planning inspector or a panel of up to five inspectors who are employed by the Planning Inspectorate. The Planning Inspectorate makes the appointment after considering the nature, scale and complexity of the case.

Examination library (commonly abbreviated as ‘EL’)

Each application (#application) will have a library of all the comments and documents that have been submitted and published on the project information page of the Find a National Infrastructure Project website (https://national-infrastructure-consenting.planninginspectorate.gov.uk/). The library is a list of all the individual documents, including the application documents, comments, plans, and statements and is updated regularly during the examination. Each item in the list is given an individual reference number.

Flood risk assessment (commonly abbreviated as ‘FRA’)

A document setting out how a development has taken account of the need to mitigate the risk of flooding. The flood risk assessment is submitted by the applicant as part of the application (#application).

Habitats regulations assessment (commonly abbreviated as ‘HRA’)

The assessment of the impacts of implementing a plan or policy on a site required under the Habitats Directive. The habitats regulations assessment is submitted by the applicant as part of the application (#application).

Hearing

A formal and structured meeting held during the examination (#examination) and led by the Examining Authority (#examining-authority-commonly-abbreviated-as-exa). See also compulsory acquisition (#compulsory-acquisition-hearing-commonly-abbreviated-as-cah) hearing, open floor hearing (#open-floor-hearing-commonly-abbreviated-as-ofh) and issue specific hearing (#issue-specific-hearing-commonly-abbreviated-as-ish).

Initial assessment of principal issues (commonly abbreviated as ‘IAPI’)

This is the Examining Authority’s (#examining-authority-commonly-abbreviated-as-exa) first thoughts about the main issues that might be involved in the examination (#examination) of the application (#application). Although the Examining Authority will identify the main matters for examination at this stage, it will still consider other important and relevant matters or topics which may arise during the examination.

Interest in land

This means a legal interest that a person or organisation has in the land that could be affected by a development consent order (#development-consent-order-commonly-abbreviated-as-dco). Examples of interests in land include where a person owns, leases, rents, or occupies the land or has some other legal right over or in relation to it.

Interested party (commonly abbreviated as ‘IP’)

An interested party is a person or organisation with special rights in the Planning Act 2008 (#planning-act-2008-commonly-abbreviated-as-pa2008) process. An interested party has the right to:
- be invited to a preliminary meeting (#preliminary-meeting-commonly-abbreviated-as-pm)
- request to speak at an open floor hearing (#open-floor-hearing-commonly-abbreviated-as-ofh)
- make further written representations (#written-representation)
- be notified when the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) has completed its examination (#examination)
- be notified of the reasons for the decision by the Secretary of State about whether the development consent order (#development-consent-order-commonly-abbreviated-as-dco) should be approved or refused
The applicant (#applicant), affected persons (#affected-person-commonly-abbreviated-as-ap) and certain statutory bodies (#statutory-body) are interested parties (#interested-party-commonly-abbreviated-as-ip), and members of the public can register to become an interested party by making a relevant representation (#relevant-representation-commonly-abbreviated-as-rr).

Issue specific hearing (commonly abbreviated as ‘ISH’)

A hearing (#hearing) about specific issues associated with the project (#project). The Examining Authority (#examining-authority-commonly-abbreviated-as-exa) will decide whether to hold these hearings and what they will be about. They will be held if the Examining Authority thinks it is necessary to find out more about an issue that it has read about in the application (#application) documents or comments made by interested parties (#interested-party-commonly-abbreviated-as-ip).

Local impact report (commonly abbreviated as ‘LIR’)

A local impact report is a written report submitted by a local authority which gives details of the likely impact of the project (#project) on the local authority’s area. A joint local impact report may be prepared if neighbouring local authorities wish to make a joint statement.

National policy statement (commonly abbreviated as ‘NPS’)

National policy statements set out the policy framework for the development of nationally significant infrastructure projects (#nationally-significant-infrastructure-project-commonly-abbreviated-as-nsip). The Examining Authority (#examining-authority-commonly-abbreviated-as-exa) in making its recommendation, and the Secretary of State in determining an application, must have regard to the relevant national policy statement or statements for the application. See this page for more information about national policy statements (https://www.gov.uk/guidance/nationally-significant-infrastructure-projects-national-policy-statements).

Nationally significant infrastructure project (commonly abbreviated as ‘NSIP’)

Nationally significant infrastructure projects are large scale major development projects in England or Wales which require permission under the Planning Act 2008 (#planning-act-2008-commonly-abbreviated-as-pa2008). They can be projects such as:
- power generating stations, offshore wind farms, electricity lines
- new roads, railway lines, airports
- hazardous waste facilities
- waste-water treatment plants
- reservoirs
Projects are only defined as nationally significant if they meet the relevant threshold set out in the Planning Act 2008 (#planning-act-2008-commonly-abbreviated-as-pa2008).

Open floor hearing (commonly abbreviated as ‘OFH’)

A hearing for interested parties (#interested-party-commonly-abbreviated-as-ip) to speak directly to the Examining Authority about their views on the application (#application). Only interested parties have the right to speak at an open floor hearing.

Oral representation

This is the term used to describe spoken evidence provided at a hearing (#hearing). Oral representations must be based on either the relevant representation (#relevant-representation-commonly-abbreviated-as-rr) or written representations (#written-representation) already made.

Order land

The land over which the application is seeking compulsory acquisition (#compulsory-acquisition-hearing-commonly-abbreviated-as-cah) or temporary possession (#temporary-possession-commonly-abbreviated-as-tp) powers. The order land must be identified in a land plan provided with the application (#application), with individual plots listed in a book of reference (#book-of-reference-commonly-abbreviated-as-bor).

Order limits

The geographic limits of the powers the applicant (#applicant) is seeking through the development consent order (#development-consent-order-commonly-abbreviated-as-dco). The order limits are typically identified by a continuous red line on plans provided with the application.

Planning Act 2008 (commonly abbreviated as ‘PA2008’)

The Planning Act 2008 (https://www.legislation.gov.uk/ukpga/2008/29/contents) is a UK law that established a streamlined process for approving nationally significant infrastructure projects (#nationally-significant-infrastructure-project-commonly-abbreviated-as-nsip) in areas like energy, transport, water, wastewater and waste. It introduced national policy statements (#national-policy-statement-commonly-abbreviated-as-nps) which set out government policy for different types of infrastructure. The Planning Act 2008 is supported by a collection of secondary legislation.

Preliminary meeting (commonly abbreviated as ‘PM’)

This is a procedural meeting held after the relevant representation (#relevant-representation-commonly-abbreviated-as-rr) period has closed. At the preliminary meeting the Examining Authority will explain the examination (#examination) process, the initial assessment of principal issues (#initial-assessment-of-principal-issues-commonly-abbreviated-as-iapi) and the draft timetable for the examination. The preliminary meeting is not the time for interested parties to say what they like or don’t like about the project.

Principal areas of disagreement summary statement (commonly abbreviated as ‘PADSS’)

Principal areas of disagreement summary statements are documents that can be prepared by certain interested parties (#interested-party-commonly-abbreviated-as-ip) to set out the main areas of disagreement with the applicant (#applicant) about the project (#project). They are provided by the interested party to the applicant at the end of the pre-application stage and included in the application (#application) documents.

Procedural decision

Procedural decisions are decisions made by the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) about how the application is to be examined. The Examining Authority must notify all interested parties (#interested-party-commonly-abbreviated-as-ip) each time it makes a procedural decision.

Project

This is the proposed development, such as a power station, offshore wind farm, section of railway, road, or electricity line for which development consent is being sought in the application (#application).

Relevant compensation claim

Claims can be made by people or organisations who might be entitled to make a relevant claim for compensation if consent is granted for the project and the development consent order (#development-consent-order-commonly-abbreviated-as-dco) is fully implemented. A relevant claim means a claim under:
- section 10 of the Compulsory Purchase Act 1965 (https://www.legislation.gov.uk/ukpga/1965/56/contents)
- part 1 of the Land Compensation Act 1973 (https://www.legislation.gov.uk/ukpga/1973/26/contents)
- section 152(3) of the Planning Act 2008 (https://www.legislation.gov.uk/ukpga/2008/29/contents)
Relevant representation (commonly abbreviated as ‘RR’)

A relevant representation is a person’s or organisation’s detailed comments about a nationally significant infrastructure projects (#nationally-significant-infrastructure-project-commonly-abbreviated-as-nsip). A relevant representation should include full details of the issues that the person or organisation want to be considered, including any evidence. This means a relevant representation should not just say ‘we support’ or ‘we object’ to the project (#project). The relevant representation must be submitted on a registration form and be received before by the notified deadline.

Report on the implications for European sites (commonly abbreviated as ‘RIES’)

The Examining Authority (#examining-authority-commonly-abbreviated-as-exa) report to the Secretary of State describing the potential effects of the project on nature conservation issues, specifically on European sites identified under the Habitats Regulations.

Representation

There are 3 types of representations that can be made about a project (#project):
- relevant representation (#relevant-representation-commonly-abbreviated-as-rr)
- written representations (#written-representation)
- oral representation (#oral-representation)
Rule 6 letter

This is a letter from the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) inviting parties to the preliminary meeting (#preliminary-meeting-commonly-abbreviated-as-pm). It is issued under rule 6 of The Infrastructure Planning (Examination Procedure) Rules 2010 (https://www.legislation.gov.uk/uksi/2010/103/contents/made) and must be sent to interested parties (#interested-party-commonly-abbreviated-as-ip) at least 21 days in advance of the preliminary meeting. As well as providing notice of the date, time and place of the preliminary meeting, the rule 6 letter will include a draft examination timetable and other decisions made by the Examining Authority.

Rule 8 letter

This is a letter from the Examining Authority sent after the preliminary meeting (#preliminary-meeting-commonly-abbreviated-as-pm) confirming the timetable for the examination. It is issued under rule 8 of The Infrastructure Planning (Examination Procedure) Rules 2010 (https://www.legislation.gov.uk/uksi/2010/103/contents/made). The rule 8 letter will also include other decisions made by the Examining Authority and can sometimes include notification of hearings (#hearing) or an accompanied site inspection (#accompanied-site-inspection-commonly-abbreviated-as-asi).

Statement of common ground (commonly abbreviated as ‘SoCG’)

A statement of common ground is a statement agreed between the applicant (#applicant) and another party which identifies matters that are not in dispute or need not be the subject of further evidence. It also identifies where the differences between parties lie and the reasons for any disagreement or outstanding matters. Statements of common ground include different types of evidence and differ from principal areas of disagreement summary statements (#principal-areas-of-disagreement-summary-statement-commonly-abbreviated-as-padss) because they are owned and authored by the applicant.

Statutory body

A statutory body is an organisation established by law with specific expert responsibilities or local knowledge. Examples of statutory bodies include Natural England, The Environment Agency and Historic England. Statutory bodies must confirm to the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) if they wish to be treated as an interested parties (#interested-party-commonly-abbreviated-as-ip) in the Examination (#examination) of an application (#application).

Temporary possession (commonly abbreviated as ‘TP’)

Temporary possession refers to the legal power that allows the applicant (#applicant) to take control of land and rights over land for a limited period of time, without permanently acquiring it.

Unaccompanied site inspection (commonly abbreviated as ‘USI’)

An unaccompanied site inspection is a visit to the application site and its surrounding by the Examining Authority (#examining-authority-commonly-abbreviated-as-exa) which does not include other interested parties (#interested-party-commonly-abbreviated-as-ip). It is an opportunity for the Examining Authority to see the area affected by the project (#project) from publicly accessible land.

Written representation

An opportunity for interested parties (#interested-party-commonly-abbreviated-as-ip) to add to the comments in their relevant representation (#relevant-representation-commonly-abbreviated-as-rr) and provide further evidence if necessary. interested parties do not have to submit a written representation and should not repeat the comments made in their relevant representation.