"Provided that it does not result in disproportionate additions over and above the size of the original building, the extension or alteration of dwellings is not inappropriate in Green Belts. The replacement of existing dwellings need not be inappropriate, providing the new dwelling is not materially larger than the dwelling it replaces. Development plans should make clear the approach local planning authorities will take, including the circumstances (if any) under which replacement dwellings are acceptable."
"It is not considered desirable to state categorically what maximum size of extension outside settlements is permissible given the wide range of circumstances to which the policy applies, other than the general requirement that it should not result in disproportionate additions taking into account the size of the extension itself on the openness of the Green Belt and the visual amenities of the Green Belt in terms of its size, scale, design, materials and character. Small extensions, even where there have been a number of previous extensions to the original dwelling, will not necessarily be refused. 'Original building' means the dwelling and domestic outbuildings as existing on1 July 1948 ; or if no dwelling existed on that date then 'original building' means the dwelling as first built after1 July 1948 , excluding any extensions or outbuildings built after completion of the dwelling."
"National guidance in PPG2 (Green Belts) sets out a general presumption against inappropriate development within Green Belts. Such development should not be approved except in very special circumstances. Paragraph 3.4 of the guidance states that the construction of new buildings inside a Green Belt is inappropriate unless it is for one of the purposes clearly specified in that paragraph. The list includes the 'limited extension, alteration or replacement of existing dwellings'. This exception is further defined in paragraph 3.6 of PPG2, which states: 'Provided that it does not result in disproportionate additions over and above the size of the original building the extension or alteration of dwellings is not inappropriate in Green Belts'."
"It is clear from the evidence adduced on behalf of the appellants and from my inspection of the subject property, including its internal layout, that Fallows End is one of the smallest houses on the estate, although it sits within one of the largest domestic curtilages. I accept that the existing internal layout in terms of both the living and bedroom accommodation is limited and that the proposed extension will provide a more balanced layout appropriate to the spacious plot within which the house is sited. In terms of the enhanced and extended accommodation I do not consider that the scheme will be disproportionate given that a larger living room and principal bedroom will be created more in keeping with modern expectations, whilst the provision of a small music room and second bedroom (making five bedrooms in all) will not be disproportionate to the existing four bedroom first floor accommodation, which is of somewhat constrained proportions."
"Furthermore, its impact upon the openness of the Green Belt will be minimal and in policy terms, as outlined above, is permitted by virtue of the exceptions set out in the Development Plan and in PPG2."
"36. The reasons for a decision must be intelligible and they must be adequate. They must enable the reader to understand why the matter was decided as it was and what conclusions were reached on the 'principal important controversial issues', disclosing how any issue of law or fact was resolved. Reasons can be briefly stated, the degree of particularity required depending entirely on the nature of the issues falling for decision. The reasoning must not give rise to a substantial doubt as to whether the decision-maker erred in law, for example by misunderstanding some relevant policy or some other important matter or by failing to reach a rational decision on relevant grounds. But such adverse inference will not readily be drawn. The reasons need refer only to the main issues in the dispute, not to every material consideration. They should enable disappointed developers to assess their prospects of obtaining some alternative development permission, or, as the case may be, their unsuccessful opponents to understand how the policy or approach underlying the grant of permission may impact upon future such applications. Decision letters must be read in a straightforward manner, recognising that they are addressed to parties well aware of the issues involved and the arguments advanced. A reasons challenge will only succeed if the party aggrieved can satisfy the court that he has genuinely been substantially prejudiced by the failure to provide an adequately reasoned decision."
"36. .... 'Limited' to my mind implies a limitation of size. Paragraph 3.6 deals with both extension and replacement. An extension must be 'proportionate' to the size of 'the original building'. The emphasis given to the word 'original' shows how tightly this is intended to be drawn, in order presumably to avoid a gradual accretion of extensions, each arguably 'proportionate'. It would be impossible, in my view, to argue that 'proportionate' in this context is unrelated to relative size. For example, an extension three times the size of the original, however beautifully and unobtrusively designed, could not, in my view, be regarded as 'proportionate' in the ordinary sense of that word." 25. "