Permission in principle and the small site limit

Permission in principle is only available by application for small housing-led schemes: fewer than ten dwellings on a site of less than one hectare, which is to say development that is not major development. Above that, the route closes and you are back to outline or full planning permission. The limit comes from the Town and Country Planning (Permission in Principle) Order 2017, made under powers inserted into the Town and Country Planning Act 1990 by the Housing and Planning Act 2016.

For a self-builder or a small developer, the attraction is obvious. You can establish that houses are acceptable on a piece of land before spending money on design, surveys and a full application. The catch is how narrow the grant is.

What permission in principle grants

Three things only: the use, the location and the amount of development. Nothing else.

That means no access arrangements, no layout, no scale beyond a number of dwellings, no appearance, no landscaping and no conditions. Permission in principle cannot be granted subject to conditions at all, which is a real difference from outline permission and the reason some authorities are cautious about it.

The grant is expressed as the site, the use, and a range or maximum number of homes. Everything else is left to the second stage.

The small site limit in detail

The application route is limited to development that is housing-led and not major. In practice that means:

• Fewer than ten dwellings
• A site area below one hectare
• Housing as the predominant use, with other uses permitted alongside it
• Not environmental impact assessment development
• Not development requiring an appropriate assessment under the Habitats Regulations

The housing-led test is worth pausing on. A scheme of four houses with a small workshop can qualify. A scheme with a large commercial element and a couple of flats on top will not, because housing is not predominant.

The other route to permission in principle is entry on Part 2 of a local authority's brownfield land register, which the authority controls rather than the applicant. Most people reading this will be using the application route.

The two-stage clock

Permission in principle by application is determined in a shorter period than a full application, and the second stage runs on its own timetable.

The permission in principle has a limited life, and the application for technical details consent must be made within it. Diarise that date on the day the grant is issued, because letting it lapse throws away the whole exercise.

Fees for permission in principle are charged by reference to site area rather than by dwelling, and national planning fees have been indexed annually since April 2025, so check the current fee schedule before you calculate the cost.

What it cannot do for you

Access is the recurring disappointment. On a rural plot or a backland site, the argument that actually decides the application is usually whether a safe vehicular access can be formed. Permission in principle does not settle it, and a grant obtained without resolving access can be followed by a refusal of technical details consent on highway grounds.

Similarly, permission in principle does not release you from anything at the second stage. Flood risk, contamination, ecology, trees, heritage and drainage all arrive at technical details consent. A Planning Statement at stage one is short, but the evidence base at stage two is the same as it would have been for a full application.

The biodiversity gain condition is applied at the technical details stage rather than to the permission in principle. That means a Biodiversity Net Gain Assessment and an approved biodiversity gain plan are still required before development can begin, unless an exemption applies. Under the Environment Act 2021 regime the statutory metric is expected to be completed by a competent person and the gain plan approved by the local planning authority, so build the ecological work into the programme early rather than treating stage two as a formality.

Technical details consent

The second application supplies what the first left out: layout, scale, appearance, landscaping and access, plus the technical evidence. It is determined against the permission in principle, so the authority cannot revisit whether housing is acceptable in principle unless circumstances have changed materially.

Two things to get right. First, keep the technical details application within the parameters of the permission in principle, because a scheme for eleven houses cannot sit on a permission in principle for a maximum of nine. Second, expect conditions, since this is the stage where they are imposed.

The determination period for technical details consent on a minor scheme is short, which sounds attractive until you remember that every survey, drawing and calculation has to be ready on the day you submit. There is no room to send information in during the process.

Illustrative example: a paddock of 0.4 hectares on the edge of a village, allocated for nothing, adjoining the settlement boundary. The landowner is unsure whether the council will accept residential use at all. Permission in principle for up to five dwellings tests exactly that question for the cost of a short statement, a site plan and a fee based on area. If it succeeds, the design work follows. If it fails, the loss is measured in hundreds rather than thousands.

The same logic applies to a garden plot in a suburban street where the council has resisted backland development before, or to a redundant farm building where the question is whether residential use is acceptable at all rather than what the house should look like.

Publicity is a further difference from a private conversation with the case officer. The authority must advertise a permission in principle application, and neighbours can comment on the principle, so objections at stage one carry into the officer's assessment in the ordinary way.

Choosing between permission in principle and outline

Outline permission remains the better instrument for most sites. It can be granted subject to conditions, it can deal with access at the outline stage while reserving the rest, and it is familiar to every officer and every lender.

Permission in principle earns its place in one situation above all: where the principle of residential development is uncertain and the cost of establishing it matters more than the breadth of the grant. Testing a marginal site at low cost is what it is for.

Where the principle is not in doubt but the design is, use outline with reserved matters. Where both are settled, apply in full and be done with it. And check that any lender or purchaser you are dealing with understands what a permission in principle is, because it is still unfamiliar enough that valuers occasionally treat it as worth less than it is.

Browse the full list of report types to see what the technical details stage is likely to require for your site.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.