Outline permission: what to fix and what to reserve

Outline planning permission with reserved matters is a tool for fixing the principle of development while leaving detail to later, and the usual mistake is reserving too much. Each of the five reserved matters you leave open is a question the authority has to be satisfied about twice: once in principle at outline, once in detail afterwards. Reserve everything and you buy an outline consent so loose that the authority refuses it, or grants it with conditions so prescriptive that the flexibility has gone anyway.

The useful discipline is to ask, for each matter, whether it is what makes the scheme acceptable. If it is, fix it.

What the five reserved matters cover

Article 2 of the Development Management Procedure Order 2015 defines them.

Access covers accessibility to and within the site for vehicles, cycles and pedestrians, including the positioning and treatment of access and circulation routes and how those connect to the surrounding network.

Appearance covers the visual impression the buildings and spaces make, including external built form, architecture, materials, lighting, colour and texture.

Landscaping covers the treatment of land other than buildings for the purpose of protecting or improving the amenities of the site and the area.

Layout covers how buildings, routes and open spaces are situated and orientated in relation to each other and to things outside the site.

Scale covers the height, width and length of each proposed building in relation to its surroundings.

Note what article 5 still requires even where layout, scale and access are reserved: the use or uses proposed, the amount of development proposed for each use, indicative access points, and upper and lower limits for the height, width and length of each building. So an outline application is never a blank sheet with a red line.

Why access is usually settled at outline

On any site where the highway authority has a view, reserving access is a false economy.

The reason is that the acceptability of the development frequently turns on whether a safe and suitable access can be achieved, and that is a question the authority will not take on trust. Reserving it invites a holding objection from the highway authority, which converts into a refusal or a long negotiation during determination anyway.

Fixing access means submitting an access drawing showing the position, the geometry, the visibility splays and any off-site works, supported by a Transport Assessment where the scheme is above the trip-generation thresholds the authority applies. Councils usually expect a suitably qualified author for transport work and professional review is strongly advised.

There is a secondary benefit. An access fixed at outline is an access you can build off-site works for under a highway agreement without waiting for reserved matters approval, which helps the programme on a phased site.

Parameter plans and how tightly to draw them

Parameter plans are not a statutory concept. They are the practical mechanism by which an outline permission is given enough definition to be assessed, usually secured by a condition requiring reserved matters to accord with them.

What works:

What causes trouble: exact building footprints, fixed storey counts, parking numbers tied to a specific layout, and anything expressed as a single figure where a range would do. Each of those turns a detailed design decision into a section 73 application.

Express heights above a stated datum rather than in storeys. A scheme that moves from 3.0 m to 3.3 m floor-to-floor for a service reason stays within a height parameter and breaches a storey parameter.

Give yourself a tolerance and say so on the drawing. A zone boundary with a 2 m tolerance either side absorbs the ordinary movement of detailed design without needing an amendment.

Conditions imposed at outline and their later effect

Outline conditions survive into reserved matters and often constrain the detail more than the parameter plans do. Read the draft conditions with the detailed design in mind, not just the principle.

Four to look at closely. A condition requiring reserved matters to accord with an illustrative masterplan, which is the single most common drafting error on outline permissions. A condition fixing the number of dwellings precisely rather than as a maximum. A condition requiring approval of materials before any development, which blocks enabling works. And a pre-commencement condition requiring a scheme that cannot be designed until reserved matters are approved, which creates a circular dependency.

Raise all of them before the decision issues. Varying them afterwards costs a section 73 application and the delay that goes with it, and where obligations are involved, varying a section 106 agreement later is a separate and slower exercise again.

Time limits under section 92

The default position in section 92 of the Town and Country Planning Act 1990 is that an application for approval of reserved matters must be made not later than three years from the grant of outline permission, and the development must begin not later than two years from the final approval of the last reserved matter.

Authorities can and do impose different periods. On a large site it is worth asking for longer at the application stage, with a programme to justify it, because an extended period is far easier to obtain before the grant than afterwards. There is no renewal mechanism for an expired outline permission, so a lapsed consent means starting again against whatever policy applies at that point.

Two practical consequences for a developer. The three year period runs from the grant, so time spent negotiating the section 106 agreement before the decision issues does not count against you. And "final approval of the last reserved matter" on a phased scheme needs care, because the phrase interacts awkwardly with phased reserved matters submissions.

Illustrative material and when it binds you

Illustrative masterplans sell schemes. They also get listed among the approved drawings, and once they are on the decision notice they bind the development.

Three protective steps:

1. Title every illustrative drawing clearly, with the words illustrative and for information only in the title block, not in a footnote.
2. Write to the case officer before the decision asking that the illustrative drawings be excluded from the approved plans list, and keep the reply.
3. Check the decision notice when it arrives. If an illustrative plan has been listed, raise it immediately rather than discovering it at reserved matters stage.

The honest tension here is that illustrative material is what persuades members and the public, and a scheme presented only as coloured parameter zones is harder to support at committee. The answer is to produce the illustrative material and to be disciplined about its status, including in the Design and Access Statement, which should state plainly which drawings are for approval and which are for information.

Where the development is EIA development, the assessment has to consider a realistic worst case within the parameters rather than the illustrative scheme. The approach in R v Rochdale Metropolitan Borough Council is indicative of how that is handled. An Environmental Impact Assessment must be prepared by competent experts under the Town and Country Planning (Environmental Impact Assessment) Regulations 2017, and that is a legal requirement rather than a matter of good practice. For specialist technical reports, qualified professional input may be required.

Phasing reserved matters across a large site

On a site of several hundred units, a single reserved matters application for the whole development is impractical. The usual mechanism is a condition requiring a phasing plan to be approved, after which reserved matters are submitted phase by phase.

Draft the phasing condition carefully. It should allow phases to be amended by agreement, allow phases to come forward in a different order, and tie the infrastructure triggers to phases rather than to dwelling numbers across the whole site where possible. A phasing plan that locks delivery into a sequence is a liability when the market moves.

Keep the time limits in view. Where the outline requires a reserved matters application within three years, submitting one phase within that period preserves the permission for that phase, and the position on later phases depends on how the conditions were drafted. Get that specific point confirmed in writing before the decision issues, because it is the one that strands sites.

Before submitting, it is worth scoping the evidence base an outline application needs, since an outline on a major site attracts most of the same technical work as a full application.

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.