Planning Inspectorate publishes guidance on preparing applications for linear nationally significant infrastructure projects

On 27 February 2025, the Planning Inspectorate (“PINS”) published new guidance relating to the preparation of applications for linear nationally significant infrastructure projects (“NSIPs”), such as electric lines, gas transporter pipelines and onshore transmission works associated with offshore wind generating stations. The guidance is non-statutory but is drawn from good practice and PINS state that applicants and others should follow their recommendations.

The guidance focuses on examples from other NSIPs and good practice and is intended to address the unique nature of linear NSIPs, which can span multiple geographic regions, administrative areas, communities and even countries. It is relevant to applicants, interested persons (e.g. local authorities, statutory consultees and local communities) and affected persons (i.e. those with rights over land (including statutory undertakers)). We have considered the key elements of the guidance below, which we have separated into the categories of key considerations for linear NSIPs and information relating to consultation and engagement for linear NSIPs. 

Key considerations for linear NSIPs

The guidance covers a wide range of matters that are relevant to linear NSIPs and should be considered by any applicant. We have summarised some of the key topics it covers below:

• the environmental statement and ensuring that it reports on the NSIP as a whole (in addition to reporting effects section by section);
• limits of deviation for the proposed development, which must be clearly established and justified; 
• the proposed order limits, which must be clearly established and justified (including an explanation of any interface with other NSIPs);
• the evolution of design, optioneering and alternatives, including having a clearly structured process setting out how the preferred routeing was determined and a justification of any alternatives that were considered but not chosen;
• the development consent order (“DCO”), including recognition that the DCO may need to include different options (to account for future commercial delivery alternatives or technological advancement) as well as flexibility as to the level of detail provided pre-consent (here the focus is on the assessment of worst-case scenarios and having a clear and secured basis for post-consent approvals);
• the phasing and timing of construction works, working hours, and the strategic approach to construction accesses;
• construction compounds and working areas, including the provision of information on the activities taking place in each construction compound or working area, the extent of land required for each and the length of time it is needed for;
• the promotion of joint working arrangements between projects to minimise adverse effects (such as sharing access routes) and the use of ‘good neighbour’ agreements (such as in relation to shared cable corridors);
• the use of localised landform options for importing material or the export of surplus material (from cut and fill), reuse of materials and the assessment of CO₂ emissions in the case of route-wide movement of materials; and
• the assessment of the health and wellbeing of local communities, the effects of severance in relation to public rights of way and the potential for projects to create improvements or operational stage benefits.

Of particular importance to linear projects is the need to secure sufficient order limits and any flexibility required to deliver the project (whether by building optionality into the DCO in relation to routeing or technology types, by securing limits of deviation to enable micro-siting infrastructure or adaptation to ground conditions, or by retaining flexibility for the detailed design stage of the project once development consent has been obtained). The guidance is also helpful to applicants as it highlights some of the areas where PINS will expect to see detailed information, such as in relation to the process taken to determine the preferred routeing of the project and the strategic approach taken to construction accesses across the route as a whole, which will not be as relevant to single-sited infrastructure.  

Consultation and engagement for linear NSIPs

A key theme of the guidance is the importance of early engagement due to the large number of interested parties and affected persons that can be involved in a linear NSIP. The guidance recommends that applicants provide details of fundamental elements of the project up front and in a single place, such as the design approach document or the design and access statement. Additionally, applicants are encouraged to carry out wide community engagement early in the process, which takes account of whether groups are likely to have an interest in the entire route of the project, or specific elements or locations of the project only. 

The guidance suggests that applicants and affected parties should recognise that the time for consultation on routeing and to make any changes is during pre-application and that given the large number of interests involved the aim should be to engage early and reach agreement before the application is submitted. It is also recognised that linear NSIPs may have multiple interfaces with statutory undertakers’ rights and assets so applicants should engage with statutory undertakers at an early stage and PINS’ will expect statutory undertakers to engage constructively and early with applicants. It is also noted that where bespoke protective provisions are required for statutory undertakers, the aim should be to include agreed protective provisions in the application DCO to save time at the examination stage. 

The guidance also recognises the benefit of joint working between organisations to improve the efficiency of the process. For example, it confirms that it is considered good practice for local authorities to organise themselves into a ‘joint council’ where a linear NSIP affects multiple local authority areas, submitting a joint local impact report and being represented at hearings by counsel. The guidance also notes that statutory undertakers or internal drainage boards may wish to engage the applicant and represent themselves jointly.

Additionally, the guidance encourages the use of plans and illustrations for consultation and in the application for the DCO, noting that illustrative materials may reduce time needed for hearings and the need for questions and may also aid understanding of the proposals during engagement and consultation. The guidance makes reference to a number of illustrative documents which have been used by previous NSIPs including schematic routeing representations, schematic sections, images of similar infrastructure, colour studies, illustrations of construction techniques, indicative timelines, site-specific composite overlay plans and physical models. 

Conclusion

The guidance provides a helpful overview of the key issues which applicants should consider and address when bringing forward a linear NSIP, as well as the matters that PINS is likely to have particular regard to when compared to an application for single-sited infrastructure. It reinforces the importance of early engagement given the potential for large numbers of interested parties and affected persons and highlights that parties such as statutory undertakers are expected to engage constructively with applicants to seek to agree matters early on. Moreover, the guidance presents several practical suggestions to improve the efficiency of linear NSIP applications, such as encouraging the use of plans and illustrations at the consultation and application stages and highlighting the potential efficiencies that can be achieved where local authorities or statutory undertakers make representations jointly. 

Burges Salmon are experienced DCO and NSIP lawyers, promoting a range of linear projects, including the pipeline project recently awarded the National Infrastructure Planning Association’s “project of the year” award for 2024.   If you have any questions or would otherwise like to discuss any issue raised in this article, please contact Alex Minhinick.