Outline permission or permission in principle
One is a permission with matters reserved. The other establishes location, use and amount and nothing else. The difference decides what a lender treats as a consented site.
Outline permission is a planning permission that leaves specified matters to be approved later. Permission in principle is not a planning permission at all until a technical details consent is granted to sit alongside it. That distinction decides almost everything else, including what a lender will treat as a consented site, how long you have to act, and what happens if the council changes its mind about the detail.
How each consent is structured
Outline permission is granted under section 92 of the Town and Country Planning Act 1990 and the Development Management Procedure Order 2015. The applicant identifies which of the five reserved matters are to be dealt with later, and the council determines the application on that basis. The grant is a full planning permission subject to conditions, one of which requires the reserved matters to be approved before development begins.
Permission in principle comes from section 58A of the same Act, inserted by the Housing and Planning Act 2016, with the detail in the Permission in Principle Order. It can arise in two ways. A local authority may enter a site in Part 2 of its brownfield land register, which grants permission in principle without anyone applying. Or a landowner may apply for it directly.
Permission in principle establishes three things and nothing else: the location, the land use, and the amount of development. Everything else is for the technical details consent stage, and until that consent is granted there is no permission to implement.
| Outline permission | Permission in principle | |
|---|---|---|
| Statutory basis | Section 92 of the 1990 Act | Section 58A of the 1990 Act |
| Is it a permission | Yes, subject to reserved matters | No, until technical details consent |
| Scope of the grant | The development, with matters reserved | Location, land use and amount only |
| Second stage | Reserved matters approval | Technical details consent |
| Conditions at stage one | Yes | No conditions on the principle |
| Size limits on application | None | Minor residential development only |
What is fixed and what is left open
The five reserved matters are access, appearance, landscaping, layout and scale. An outline application may reserve all of them or some of them, and it is common to fix access at outline stage because the highway authority wants certainty and because access constrains everything else.
A reserved matters application is an approval of details, not a fresh permission. The council cannot use it to revisit the principle of development, and it cannot impose conditions inconsistent with the outline grant. It can and does refuse details that are unacceptable, which is why the illustrative material submitted at outline stage matters. Parameters set out in a development framework, and conditions tying later approval to those parameters, give both sides something to work to. There is more on that boundary in the note on what outline permission leaves open.
Permission in principle fixes less. The amount of development has to be expressed as a number of dwellings, usually as a minimum and a maximum, and the use has to be residential-led. Nothing about access, drainage, ecology, amenity or design is settled. Those all fall to be considered at technical details consent, and the council can refuse that application on any of them.
Site size and use limits on permission in principle
The application route is limited to minor development. In practice that means a residential-led scheme of fewer than 10 dwellings on a site smaller than one hectare.
Other exclusions apply. Permission in principle is not available for development requiring environmental impact assessment, nor where a habitats assessment would be needed, and it is a residential-led route rather than a general one. Non-housing floorspace can form part of a scheme where housing predominates, within the limits in the Order.
The brownfield land register route works differently. A council enters a site in Part 2 of the register on its own initiative after consultation and publicity, and permission in principle follows from the entry. Landowners can ask to be considered for entry, which is covered in the note on brownfield land registers and permission in principle.
Technical details consent and its timetable
The technical details application is where the scheme is actually assessed. It must accord with the permission in principle, meaning the location, use and amount already established, and the council considers everything else.
Statutory determination periods are short for permission in principle on application and for a technical details consent on minor development, and longer where the technical details application is for major development. Check the current periods in the Order before relying on a programme, because they differ from the eight and thirteen week periods people are used to.
The practical consequence is that the evidence base is the same as for a full application. A site needing a flood risk assessment, an ecological appraisal and a transport statement needs all three at technical details stage. Permission in principle removes an argument about the principle. It does not remove any survey.
Time limits for implementation
The clocks differ and this is where sites are lost.
An outline permission normally requires reserved matters to be applied for within three years of the outline grant, and the development to begin within two years of the final approval of reserved matters. Councils can and do vary those periods by condition, so read the decision notice rather than assuming the default.
Permission in principle granted on application has effect for three years. Permission in principle arising from an entry in Part 2 of the brownfield land register has effect for five years. If technical details consent is not granted within the period, the permission in principle lapses.
Diary both dates the moment either consent is issued. The approach to keeping consents alive is set out in time limits on permissions and how to keep one alive.
Which sites suit which route
Permission in principle suits a small site where the only real question is whether housing is acceptable there at all. A single infill plot in a village with a restrictive settlement boundary policy, a garden plot, a redundant yard within a built-up area. It is quick, the fee is modest, and a refusal tells you early that the site is not worth more investment.
Outline permission suits everything larger, anything phased, and any site where the applicant wants to fix access, secure a parameter plan, or attach a section 106 agreement at the first stage. It also suits sites being sold, because the market understands it.
A third option is worth stating plainly. On a single self-build plot where the design is settled, a full application is often the better route, because it produces one decision rather than two and the aggregate fee and professional cost can be lower.
Lender and land value considerations
Valuers and lenders treat outline permission as a consented site. Permission in principle without technical details consent is less familiar, and some lenders and buyers discount it or treat it as equivalent to an allocation rather than a consent.
That is a market observation rather than a legal one, and it is changing. But if the purpose of obtaining consent is to sell the land or to borrow against it, ask the intended lender or agent what they will treat as sufficient before choosing the route.
Where a scheme needs a supporting narrative at either stage, a focused Planning Statement setting the proposal against the development plan does more work than a long design rationale. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.
Frequently asked questions
Is permission in principle a planning permission?
Not on its own. It establishes the location, the land use and the amount of development, and nothing else. A technical details consent has to be granted alongside it before there is anything to implement. Until then, access, drainage, ecology, amenity and design are all unresolved.
What are the reserved matters?
Access, appearance, landscaping, layout and scale. An outline application may reserve all or some of them. Access is commonly fixed at outline stage because the highway authority wants certainty and because it constrains the rest of the layout. A reserved matters application approves details rather than granting a fresh permission.
What size of site can use permission in principle?
The application route is limited to minor residential-led development, meaning fewer than 10 dwellings on a site smaller than one hectare. It is unavailable where environmental impact assessment or a habitats assessment would be required. The brownfield land register route works differently and is initiated by the council.
How long does each consent last?
Outline permission normally requires reserved matters to be applied for within three years and development to begin within two years of final approval, subject to any different period in the conditions. Permission in principle on application lasts three years, and permission in principle from a brownfield register entry lasts five.
Does permission in principle reduce the survey work?
No. It removes an argument about whether housing is acceptable in that location, and nothing else. A site needing a flood risk assessment, an ecological appraisal and a transport statement still needs all three at technical details consent stage, where the scheme is actually assessed.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.