From personal experience of pursuing a complaint with both the Local Planning Authority and the Ombudsman, I have reached the conclusion that there exists a considerable body of information which gives the impression that the Planning Process is fair and democratic, which is an illusion that all of the Authorities involved wish to perpetuate. This information is called 'guidance', which means that it can in large part be ignored. This is in sharp contrast to Government 'Planning Policy Guidance' (PPG), which cannot. With Apologies to George Orwell ' All guidance is created equal, but some is more equal than others'. I offer the following examples of such illusions: 

As a person affected by a proposed development, you are entitled to express your concerns, and these will be considered by the Authority. This gives the impression that your comments and concerns are relevant and will be considered. There is little evidence to support this; Consider the following statement from the Solicitor to the Forest of Dean District Council: "Planning permissions are not the result of negotiations with objectors, but result from the exercise of a regulatory function whereby applications are assessed against criteria/ policies/guidance relevant to sustainable development. Negotiations may be occur between the planning officers and the applicant to overcome planning issues which impede development opportunities and these may be generated by the objections received from third parties". Only if your objection happens to coincide with identified planning issues will it appear that it has been considered.
Local Plan Policies define the environment in which you live. Although democratically prepared as required by the 1990 Act, these policies do not seem to carry the weight indicated. Consider the requirement (as given elsewhere) that development be compatible with it's surroundings in terms of density; The LPA attempted to persuade the developer to increase the density such that it represented an increase of 154%. The Ombudsman upheld this decision with the statement "The LPA must balance the need to make best use of available land with ensuring compatibility with surrounding and existing development. These are matters of judgement for the planning authority to determine and the Ombudsman cannot challenge the merits of the decision reached as I see no evidence that the Council's position is wholly unreasonable". This despite guidance given in the Ombudsman's own guidance to Councils: "In dealing with planning applications, for example, councils are required by law to have regard to the provisions of the development plan, so far as material to the application, and to any other material considerations; and must determine the application in accordance with the plan unless material considerations indicate otherwise. The plan should normally be given considerable weight in the decision, and strong contrary planning grounds would have to be demonstrated to justify a proposal which conflicts with it."
Adopted Supplementary Planning Guidance gives additional definition of the local environment. This carries the least weight of all. Although the 'Forest of Dean Residential Design Guide' is a fine publication, the LPA appears to use it in an a posteri fashion. Although it may appear to describe sensitive controls on development, this is an illusion. Consider the following statement from the former assistant head of planning: "As the title suggests, it is a guide; no discussion on design issues can ever be prescriptive. It shows good practice and principles, but there is always scope for other ideas, and an application that ignores the advice cannot be rejected on that ground alone."  
Highways requirements are considered by the LPA. Again, these appear to be applied in an a posteri fashion. The County Council "Highways requirements for Development" specifies a maximum of 50 dwellings to be served by a cul-de-sac. This is magically transformed into 'a guideline figure' and 'relate (ing) to a block of new development' by the Ombudsman. This is contrary to the view of the County Council Highways Authority, who insist that these requirements apply to ALL developments.
The LPA carries out it's duties to the highest professional standards. In it's publication 'Good Administrative Practice' the Local Government Ombudsman suggests that a Council should: "Seek appropriate specialist advice as necessary" yet when confronted with evidence from the Arboricultural Association that affected trees should be surveyed prior to a planning decision, The LPA dismissed this as 'too onerous'. When provided with the advice of a Fellow of the Arboricultural Association, suggesting that the simple conditions given in the planning consent granted by the Council would not be sufficient to prevent long term damage to a Tree to which a preservation order applies, the Ombudsman found in favour of the Council. The Ombudsman thus condones a standard of performance considerably less than would be accepted in other professions.
The Local Government Ombudsman ensures fair and reasonable behavior by Councils. In it's own publication 'Good Administrative Practice', Policy No. 4 states: "Ensure that criteria are clear and relevant and can be applied objectively so that decisions are not made on an inconsistent ad hoc or subjective basis" yet the Ombudsman has found no fault with the LPA which rejected an application for one dwelling (on the grounds of the serious effect it would have on the privacy of surrounding properties) in the past but subsequently granted permission for two dwellings.

Given so many contradictions with published information and professional standards, it is difficult to see that any rational process is employed in planning decisions. The Ombudsman has said: "A Council must determine each application on it's merits", yet in the 'Good Administrative Practice' guide, the Ombudsman cautions against "merit schemes which do not have fixed rules but deal with all cases 'on their merits'." since:

"

They are open to patronage or even corruption
They cannot be seen to be fair
They cannot operate consistently; and
They are in breach of the legal obligation to publish rules

"

I am left with the impression that planning decisions (at least those taken by this LPA ) are arrived at by a mystical process unconnected with any published guidance, the reasons for which cannot and will not be explained by those empowered to take the decisions. The worst part of this is that none of them seem to see anything wrong or unfair about it!