Some developments are too big for the local planning system to decide on at all.
A new power station, a major rail scheme, a large reservoir – projects on this scale don’t go through the local authority’s planning committee. They bypass it entirely, decided instead by central government under a completely separate regime. That regime is Nationally Significant Infrastructure Projects (NSIPs), and understanding why a scheme sits inside it changes where you’d even look to find out about it.
Here’s what makes a project an NSIP, and why that matters for anything nearby.
What is an NSIP?
The Planning Act 2008 created a distinct category of large-scale development in five sectors – energy, transport, water, waste water, and waste – that qualify as Nationally Significant Infrastructure Projects once they exceed defined statutory thresholds. An onshore generating station over 50 megawatts is a typical example of a threshold test; similar size- or capacity-based tests apply across the other sectors, covering things like electricity generating stations, rail freight interchanges, reservoirs, and hazardous waste facilities.
Since 2013, business and commercial projects that don’t automatically meet a sector threshold can also opt into the regime if the Secretary of State considers them nationally significant, so the category isn’t purely a function of the thresholds; there’s a discretionary route in as well.
Why does size change who decides?
Once a project meets the NSIP threshold, it no longer goes through the local planning authority for permission. Instead, the applicant applies to the Planning Inspectorate, which examines the proposal and makes a recommendation to the relevant Secretary of State, who takes the final decision. This has been the arrangement since April 2012, when the Planning Inspectorate took over the role from the former Infrastructure Planning Commission following the Localism Act 2011.
The logic is straightforward: projects of this scale often cross multiple local authority boundaries, involve national policy priorities that a single council isn’t well placed to weigh, and benefit from a single, consistent consenting process rather than a patchwork of separate local decisions.
What happens to the local authority’s role?
It doesn’t disappear, it changes shape. A host or neighbouring local authority becomes a statutory consultee rather than the decision-maker, and is required to produce a Local Impact Report during the examination stage, setting out the effects the project will have on its area. That report feeds into the Planning Inspectorate’s recommendation, but the authority no longer has the power to grant or refuse permission itself.
How is an NSIP actually authorised?
Through a Development Consent Order (DCO), a single consent that can bundle together permissions that would otherwise need to be applied for separately, including elements of compulsory acquisition. The process from formal acceptance of an application to a decision typically takes over a year, and is front-loaded with substantial pre-application consultation requirements before the Planning Inspectorate will even accept a submission. The mechanics of the DCO process – and what it means for landowners along a scheme’s route – are worth a piece of their own, given how much they involve.
Why does this matter for a property search?
Because an NSIP bypasses the local planning authority, the usual channels a conveyancer relies on for planning history don’t necessarily surface it in the way they would a conventional planning application. A DCO application sits with the Planning Inspectorate’s national register, not the local authority’s planning portal, and a standard local search isn’t necessarily designed to highlight a nationally significant scheme progressing through a separate, centrally administered process.
For any property near a proposed energy, transport, water, or waste scheme of real scale, that’s a reason to check the national register specifically rather than assuming a clean local search means nothing of consequence is coming. It’s also the route by which some of the most substantial compulsory acquisition and blight issues arise – an NSIP’s DCO can carry powers that touch a much wider area than the footprint of the scheme itself.
An NSIP isn’t defined by controversy or local objection, it’s defined by scale, sector, and a statutory threshold that moves the decision out of local hands entirely.
Knowing a project qualifies as an NSIP tells you immediately where to look for information about it, and it’s rarely the place a standard search would otherwise point you.
