Amendments have been made to the advice in the PPG on environmental impact assessment. Paragraph number: 035: http://planningguidance.planningportal.gov.uk/revisions/4/035/
The PPG now reads:
What information should the Environmental Statement contain?
There is no statutory provision as to the form of an Environmental Statement. However, it must contain the information specified in Part II of Schedule 4, and such of the relevant information in Part I of the Schedule 4 as is reasonably required to assess the effects of the project and which the applicant can reasonably be required to compile. It may consist of one or more documents, but it must constitute a “single and accessible compilation of the relevant environmental information and the summary in non-technical language” (Berkeley v SSETR  3 All ER 897, 908).
The applicant does not need to consult anyone about the information to be included in an Environmental Statement. However, local planning authorities will often possess useful local and specialised information and may be able to give preliminary advice on those aspects of the proposal that are likely to be of particular concern to them. It may also be helpful to an applicant preparing an Environmental Statement to obtain relevant environmental information from the statutory consultation bodies (regulation 15), and also to consult any appropriate non-statutory bodies that also have relevant information.
Whilst every Environmental Statement should provide a full factual description of the development, the emphasis of Schedule 4 is on the “main” or “significant” environmental effects to which a development is likely to give rise. The Environmental Statement should be proportionate and not be any longer than is necessary to assess properly those effects. Where, for example, only one environmental factor is likely to be significantly affected, the assessment should focus on that issue only. Impacts which have little or no significance for the particular development in question will need only very brief treatment to indicate that their possible relevance has been considered.
Where alternative approaches to development have been considered, the Environmental Statement should include an outline of the main alternatives studied and the main reasons for the choice made, taking into account the environmental effects.
The Environmental Statement may, of necessity, contain complex scientific data and analysis in a form which is not readily understandable by the lay person. The main findings must be set out in accessible plain English in a non technical summary to ensure that the findings can more readily be disseminated to the general public, and that the conclusions can be easily understood by non-experts as well as decision makers (paragraph five of Part II of Schedule 4).