Electricity Act 1989 - section 36 applications: guidance for applicants on using the design envelope

3. Case law and principles

3.1. The design envelope principle was developed from judgments in cases in the Queen's Bench Division of the High Court: R v Rochdale MBC ex parte Tew and Others (No. 1) [2000] Env L.R. 1; and R v Rochdale MBC ex parte Milne (No. 2) [2001] Env. L.R. 22. These cases dealt with challenges to decisions to grant outline planning permissions for a proposed business park in Rochdale.

3.2. Whilst these cases dealt with previous EIA regulations applicable at the time and related to outline planning permissions, a practice has since emerged of using the design envelope approach for developments requiring EIA where the final details of a project are unknown at the time the application is submitted.

3.3. The first of these cases was a challenge to the grant of outline planning permission on a number of grounds, the most relevant of which was that the information provided by the developer to describe the development failed to meet the requirements of the EIA regulations in place at that time, on the basis that the application in particular did not contain any information as to the design, size or scale of the development. The application contained an environmental statement (ES) and an ecological survey, based on an illustrative master plan and a schedule of uses. The challenge was successful and the Court's key findings relevant to this guidance can be summarised as follows:

• Whilst a "bare outline" application is permissible, an ES based on such an application could not be compliant with the EIA regulations in place at the time. In accordance with the objectives of the EIA Directive in place at the time (EC Directive 85/377 on the assessment of the effects of certain public and private projects on the environment), the information contained in the ES should have been both comprehensive and systematic, so that a decision to grant planning permission could be taken in full knowledge of the project's likely significant effects on the environment.
• The ES did not need to contain "every conceivable scrap of environmental information" about the project, but the legislation requires likely significant effects to be addressed.
• Further, it may be appropriate to give illustrative floor space figures, and then the ES could assess the impact of a range of possible figures before describing the likely significant effects. Conditions could then be imposed to ensure that any development keeps within those ranges.

3.4. In the second of these cases, the same developer revised its planning application, including a new ES, and planning permission was again granted – this case was a challenge to that decision, on the basis that a sufficient description of the development had not been provided. Although a description of the scale and size of the proposed development had been provided, the design of the scheme was not provided at that time. The challenge was unsuccessful and the Court's key findings relevant to this guidance can be summarised as follows:

• The requirement in the EU Directive to provide information on the site, design and size of the project was, and was intended to be, sufficiently flexible to accommodate the specific characteristics of different types of project and accordingly, it was possible to provide more or less information on site, design and size, depending on the nature of the project to be assessed.
• Where a project was, by its very nature, not fixed at the outset, but is expected to evolve over a number of years, there was no reason why a "description of a project" should not recognise that reality. What was important was that the EIA should then take full account at the outset of the implications for the environment of this need for an element of flexibility.
• For some projects, it will be possible to obtain a much fuller knowledge of the likely significant effects on the environment. The aim is that as much knowledge as can reasonably be obtained, given the nature of the project, about its likely significant effects is available to the decision-maker. However, it also made clear that: "This does not give developers an excuse to provide inadequate descriptions of their projects. It will be for the authority responsible for issuing the development consent to decide whether it is satisfied, given the nature of the project in question, that it has 'full knowledge' of its likely significant effects on the environment. If it considers that an unnecessary degree of flexibility, and hence uncertainty as to the likely significant environmental effects, has been incorporated into the description of the development, then it can require more detail, or refuse consent" (paragraph 95).
• In assessing likely significant effects, it is possible to adopt a "cautious worst case" approach. Such an approach will then feed into the mitigation measures, which must be adequate to deal with the worst case.

3.5. This second case was then appealed to the Court of Appeal in R v Rochdale MBC [2000] 12 WLUK 678. The Court refused the application for permission to appeal and reaffirmed the findings in R v Rochdale MBC ex parte Milne (No. 2). The Court also confirmed the following in relation to the adequacy of descriptions of development:

• What is sufficient in terms of the description of development "…is a matter of fact and degree. There is no blueprint which requires a particular amount of information to be supplied. What is necessary depends on the nature of the project and whether… enough information is supplied to enable the decision-making body to assess the effect of the particular project upon the environment." (paragraph 33)
• It is for the decision-maker to decide if the information is sufficient, but there may be cases where the court can and should intervene where it finds that no reasonable authority could have been satisfied with the amount of information it was supplied with in the particular circumstances of the case.

3.6. Certain key principles have emerged from these and subsequent cases, as well as the practical application of them. ECU and MS consider the following points as the key principles for applicants to consider when using the design envelope approach:

• Application documents should explain the need for and the timescales associated with the flexibility sought for the proposed development and this should be established within clearly defined project parameters;
• The parameters established for the proposed development must be sufficiently defined to enable a proper assessment of the likely significant environmental effects and to allow for the identification of mitigation, if necessary, within a range of possibilities;
• The assessments in the EIA report should be consistent with the clearly defined parameters and ensure a robust assessment of the likely significant effects;
• The EIA report assessment may include a "cautious worst case" approach, but that must then feed through into the mitigation measures which should be adequate to deal with the worst case; and
• Any consent given by Scottish Ministers must not permit the proposed development to extend beyond the clearly defined parameters which have been requested and assessed. Scottish Ministers may choose to impose conditions to ensure that the proposed development is constrained in this way.

3.7. It is for the applicant to be satisfied that it has provided an appropriate degree of specification in the application documentation, having regard to the receiving environment and the specific facts of an application. The EIA scoping process is beneficial to allow matters of specification and the degree of flexibility incorporated to be canvassed before an application is submitted.