Phasing a larger permission: conditions and obligations

A phasing condition planning permission changes almost every other condition on the decision notice. Triggers that read naturally on a single-phase scheme, such as before first occupation, become ambiguous when occupation happens five times across eight years. Infrastructure that serves the whole site has to be delivered during one phase and paid for by all of them. And the community infrastructure levy behaves differently, in a way that is worth money if the condition is drafted correctly and lost if it is not.

Negotiate the phasing condition itself first, then work through the rest of the schedule against it. Doing it the other way round produces a permission that cannot be built out in the order the appraisal assumes.

Why phasing changes the condition schedule

Three mechanical problems appear as soon as a site is phased.

The first is identifying what a phase is. A phasing plan approved by condition should define each phase by a boundary on a drawing, not by a description, and it should state what is in each phase: dwelling numbers, non-residential floorspace, the roads, the open space and the drainage infrastructure.

The second is the trigger problem. Pre-commencement conditions become pre-commencement of which phase. Pre-occupation conditions become pre-occupation of what. Unless each condition says, the authority and the developer will read it differently and the argument happens at the worst possible moment, which is when a plot is about to complete.

The third is the dependency problem. Some conditions can sensibly be discharged phase by phase, such as materials, levels and landscaping. Others have to be discharged once for the whole site, such as a site-wide drainage strategy or an archaeological written scheme of investigation. Classify every condition into one of those two groups before agreeing the schedule.

Trigger points expressed by phase

The drafting that works names the phase and the event.

• Before commencement of development within Phase 2, details of X shall be submitted and approved.
• Before first occupation of any dwelling within Phase 1, the works shown on drawing Y shall be completed.
• Before occupation of the 50th dwelling across the site as a whole, the spine road shall be completed to base course between points A and B.
• Before occupation of the 150th dwelling across the site as a whole, the play area in Phase 2 shall be laid out and available for use.

Note the difference between the third and fourth examples and the first two. A site-wide cumulative trigger counts dwellings across all phases, which protects the authority against a developer building out three phases while leaving the infrastructure in a fourth. A phase-specific trigger is easier for the developer to manage. Expect the authority to want cumulative triggers for anything strategic and phase triggers for everything local, and expect that to be the right answer.

Avoid two formulations. Triggers tied to a calendar date, which fail if the market stalls. And triggers tied to the commencement of a later phase, which never bite if that phase is never started.

Infrastructure delivered once but serving several phases

This is the hard part of a phased permission and it is a funding question dressed as a drafting question.

A surface water attenuation basin sized for the whole site has to be built early, because the first phase drains into it. A primary school has to be delivered when the pupil yield justifies it, which is usually part way through. A spine road has to reach each phase before that phase is occupied, but the whole length is rarely needed on day one.

Two drafting points earn their keep. First, define spine road sections on a drawing and tie each to the phase it serves, so the whole road is not required before the first house is occupied. Second, where early infrastructure is needed for a later phase's benefit, ask for a trigger expressed as the earlier of a cumulative dwelling count or the commencement of the relevant phase, which stops the obligation being triggered twice over.

Drainage is often the binding constraint, and on larger sites the lead local flood authority's approval of the site-wide strategy governs the first phase, as explained in the guide to when drainage needs flood authority approval.

The levy and phased planning permissions

Phasing has a specific and valuable consequence for the community infrastructure levy. Where a permission qualifies as a phased planning permission under the levy regulations, each phase is treated as a separate chargeable development. Liability, the commencement notice and any relief or exemption claim are then dealt with phase by phase rather than for the whole site at once.

Two practical points follow.

An outline permission permitting phased development qualifies. A detailed permission qualifies only where it is subject to a condition requiring a phasing scheme or plan. So on a full application for a large site, ask for that condition expressly, because without it the entire levy liability crystallises on the first material operation anywhere on the site.

The levy rate is indexed, and indexation is applied by reference to when each phase begins. Later phases therefore cost more per square metre than earlier ones at today's prices, which belongs in the appraisal rather than being discovered in year six.

Amendments interact with this. Varying a phased permission under section 73 brings specific levy provisions into play, and the recalculation can produce an unexpected result, so take advice before submitting the application rather than after the revised liability notice arrives.

Reserved matters by phase

On an outline permission, the standard condition requires applications for approval of reserved matters within three years and commencement within two years of the final approval. On a scheme that will take a decade, that is unworkable.

What to negotiate instead: a longer period for the submission of reserved matters, expressed by phase, with the development of each phase to begin within a stated period of the approval of that phase's reserved matters. Authorities grant this on allocated strategic sites reasonably often, because the alternative is a permission that has to be renewed mid build-out and reassessed against a changed policy position.

Keep the parameter plans no tighter than the scheme needs, since departing from them requires a section 73 application while a design code or a phasing plan can be varied by agreement. And be clear in the condition whether reserved matters for a later phase have to accord with an approved design code, because that is where most reserved matters disputes arise.

Risks of a rigid phasing plan

A phasing plan fixed at permission stage is a forecast, and forecasts about an eight-year build-out are wrong.

The failures to anticipate are familiar. A phase boundary that has to move because a drainage outfall turns out to be in the wrong place. A phase that becomes commercially unviable and is swapped with a later one. An affordable housing provider who wants a contiguous block straddling two phases. A serviced parcel sold to a different builder who wants a different boundary.

Each of those needs either a mechanism in the condition or a section 73 application. The mechanism is much better. Ask for the phasing condition to allow variation of the phasing plan with the written agreement of the local planning authority, rather than requiring a formal application for every change. Many authorities accept this, because the alternative is a stream of applications they also have to process.

The one honest caution is that a flexible phasing condition does not relax the obligations in the agreement. Those need their own flexibility, drafted separately.

Drafting flexibility into the agreement

The section 106 agreement is where phasing either works or does not, because it carries the money.

The provisions to argue for: phase definitions that cross-refer to the approved phasing plan rather than repeating it, so a varied plan flows through automatically. Triggers tied to occupation counts rather than dates. A mechanism for substituting units between phases where the overall quantum and tenure mix are maintained. An affordable housing cascade dealing with what happens if no registered provider will take the units on the agreed terms, supported by a clear Affordable Housing Statement at application stage. Release provisions so that completed plots and their occupiers are not bound by developer obligations. And mortgagee protection, which lenders will require.

Biodiversity net gain needs its own treatment on a phased scheme. The regime provides for an overall gain plan for the development together with a plan for each phase, so the Biodiversity Net Gain Assessment and the habitat management arrangements have to be structured accordingly from the outset. The metric work must be completed by a competent person under the Environment Act 2021 regime.

The wider question of how phasing interacts with the thresholds that trigger assessments is covered in the guide to phasing a large scheme without gaming thresholds.

You can see the full set of documents a phased major application draws on in the report index.

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.