Salami slicing and cumulative effects in EIA

Salami slicing is the practice of dividing a development into separate applications so that each falls below the threshold at which environmental impact assessment would be required. Screening for salami slicing in EIA terms asks a simple question. Is this application really a part of a larger project? If it is, the authority has to screen the whole project rather than the slice in front of it, and a screening opinion that fails to do so is open to challenge.

What the term describes

The EIA Regulations 2017 require assessment of projects, and a project is not defined by the boundaries of an application form. Where a scheme is split into two or three applications that together exceed a Schedule 2 threshold, each individually below it, the division does not remove the assessment duty.

The term carries an accusation of bad faith, which is unhelpful, because most splitting is commercially driven rather than tactical. A promoter who owns two adjoining fields and has funding for one of them will apply for one. That is normal practice and it is not avoidance.

The question is objective. It is whether the elements form a single project, judged by what they do and how they depend on one another, not by what the applicant intended.

Why it matters at screening stage

Schedule 2 development is screened against indicative thresholds, and for urban development projects the familiar figures are more than 150 dwellings, more than one hectare of non-residential urban development, or an overall site area exceeding five hectares.

Those thresholds are the trigger for screening rather than for assessment itself. Once screening is engaged, the authority applies the Schedule 3 selection criteria, and the first of those criteria expressly includes cumulation with other existing development and approved development.

So cumulative effect enters the analysis twice. It affects whether the threshold is reached, where applications are properly treated as one project. And it affects the significance judgement, where separate projects nonetheless combine to produce effects that matter.

How authorities identify a split project

There is no checklist in the Regulations, and officers work from the facts. The factors that recur are functional interdependence, common ownership or control, physical connection, and timing.

The courts have accepted that two applications which are functionally interdependent may need to be assessed together, so where one element cannot operate without the other the case for a single project is strong. A processing plant and the facility that supplies it, an access road and the development it serves, a car park and the building it exists for.

Public statements matter more than people expect. A website describing a single masterplan, or a committee report referring to a wider scheme, will be produced by an objector at the right moment.

Cumulative assessment where the projects are separate

Even where splitting is not in issue, cumulative effects have to be assessed. The practical difficulty is scope. Which other developments go into the baseline, and at what level of certainty.

The workable convention is a tiered approach. Built and operational schemes sit in the baseline. Consented but unbuilt schemes are assessed as committed development. Schemes with a live application are assessed where there is enough information to do so. Allocations without an application are usually noted rather than modelled.

State the list, the cut-off date and the tier for each entry, because the list is the part most often challenged. Where a neighbouring scheme is consented and your assessment ignores it, the omission is easy to find and hard to defend. Our note on intensification as a material change of use covers the related question of when incremental growth becomes development in its own right.

Phased development that is legitimately phased

Phasing is normal and lawful. A large scheme consented in outline, with reserved matters applications for each phase, has been assessed as a whole in one Environmental Statement, and the phasing happens after assessment rather than instead of it.

That is the model to use where a scheme will come forward over years. Apply for the whole thing, assess the whole thing, then build it in phases under a phasing condition. The alternative, submitting phase one and dealing with phase two later, saves assessment cost now and creates a risk that the later phase is refused or screened into EIA on cumulative grounds.

Where funding covers only part of a landholding, say so in the screening request and explain why the remainder is not a committed part of the same project. An honest explanation that the balance of the site has no scheme, no application and no funding is far more persuasive than silence.

Evidence that phases are independent

If you need to show that two applications are separate projects, assemble the evidence before the screening request rather than after the challenge.

• Separate access arrangements and separate utility connections for each element.
• A statement that each element is viable and operable on its own, with the commercial basis explained.
• Different landowners or an arm's length relationship between promoters.
• A timing explanation grounded in funding, tenancy or lease events rather than in the threshold.
• Consistency between the application, the marketing material and anything said publicly.

Where the evidence does not support independence, the better route is to accept assessment. An Environmental Statement prepared properly at the start costs less than a refusal, a judicial review, or a consent quashed after work has started.

Challenges on cumulative grounds

Screening opinions are challenged by judicial review rather than by appeal, which means a short time limit and a cost exposure. It also means a low evidential bar for the claimant. The claimant has to show the authority failed to consider something it was required to consider, and a screening opinion silent on an adjoining consented scheme is vulnerable.

The defence is a reasoned opinion. An opinion that lists the other development considered, explains why the applications are treated as separate projects, and reaches a conclusion on cumulative significance is difficult to attack even where a reasonable person might disagree with the outcome.

So ask the authority for a screening opinion in writing rather than relying on an informal view, and submit the material that lets the officer write a reasoned one. Where assessment is required, the Environmental Statement must be prepared by competent experts under the EIA Regulations 2017, so an Environmental Impact Assessment draft is a starting point for those experts rather than a substitute for them. Explain the phasing position squarely in the Planning Statement, and browse all 66 report types to see what a full assessment adds to the document set.

For specialist technical reports, qualified professional input may be required. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.