External or underground environmental factors... Q & A DCP Section 4.16

This section is concerned with the consideration of the blighting effect of conditions outside or under the site of a planning application. While housing development is the land use most likely to be sensitive to such factors, all forms of development may be subject to external inhibitants.

Q & A    4.16/10

I am dealing with an application to rebuild existing domestic garages which have been undermined, to the point of structural collapse, by the activities of badgers. Badgers are, of course a protected animal species. Paragraph 47 of PPG9 indicates that the presence of a protected animal species is a material consideration to be taken into account in the determination of an application. Some commentators indicate that the assessment of harm caused to the animals should only form part of the consideration required during the procedure to obtain a licence to allow interference with a sett. Potentially then, if planning permission was granted it could be unimplementable if no license was forthcoming. Are there any planning cases that assist in this matter?

In terms of badgers there have been several appeal cases where proposed development would physically affect setts. In a 1994 case from Waverley, where bungalows were proposed on the site of a sett, an inspector noted the provisions of the Protection of Badgers Act 1992 and the need to obtain a licence from English Nature. He observed that the existence of a sett did not necessarily preclude the grant of planning permission, and allowed the development. This approach clearly follows the line that if other legislation adequately deals with a problem it is not a material consideration in planning terms. On the other hand cases may be produced where inspectors have relied on local plan policy seeking to provide a general presumption against development which adversely affects nature conservation interests. Accordingly, a number of appeals have been dismissed on grounds of interference with setts or related areas. I suspect that the latter is the course of action that most development controllers would prefer to take given their legal duty to make a decision in accordance with the development plan unless material considerations indicate otherwise.

My council is considering granting permission for a housing development alongside a railway which runs on a 25m high embankment. Members have raised the question of whether the risk of a rail accident should be a material consideration which they ought to take into account.

This question has arisen at appeal in at least two cases and in both instances inspectors have considered that the likelihood of an accident occurring at one particular spot which would cause rolling stock to fall onto housing below, was so slight as not to be material. Of course, it may be possible to contrive the layout of any new housing development so that areas such as parking or open space are located nearest the railway line, and this may be also be desirable from the point of view of minimising noise impact.

My client wishes to commence a use for the storage of fireworks but the building is located within 25-30 metres of a grade II* listed timber framed building. English Heritage has objected on the basis that if there was an explosion the listed building would be at risk. Is this a reasonable material consideration?

The Planning (Listed Buildings and Conservation Areas) Act 1990 at section 66 imposes a general statutory duty upon local authorities to have special regard to listing buildings when determining nearby planning applications. In practice this nearly always relates to consideration of the protection of a listed building's setting. So far as I know the possibility of physical damage as a consequence of an adjoining use has not arisen before at appeal or in the courts, but I have no doubt that the concern of English Heritage is a reasonable one. In this circumstance I would have thought that some form of risk assessment would need to be carried out having regard to any safeguards proposed by the applicant. This would enable a decision to be made whether there is any reasonable likelihood of an explosion occurring which would damage the listed building. Has any reader had experience of this type of situation?


Premises that store fireworks have to be registered with the local authority. Minimum distance to any third party buildings and public highways are often required depending on the type and amount of fireworks stored, but there is a threshold below which no separation distance is required. Currently the regulation concerning the storage of fireworks and other explosives is out for consultation by the Health and Safety Executive. I would advise that the questioner get in touch with the local trading standards officer who is usually responsible for such matters.

My authority is dealing with a planning application for the construction of a large fishing lake within the consultation distance of a regional airport. Both the CAA and the airport are raising objections to the application on the grounds of risk to aircraft from bird strike. While we have no difficulty in considering this as a material consideration, we can find no reference in case law or guidance to this issue. Can you point to any helpful information?

There are several appeal cases to demonstrate that it is a material consideration in relation to proposed development that it would be likely to attract birds which could create an air safety hazard. The normal scenario is domestic waste landfill developments and in such cases it needs to be shown that there is a reasonable likelihood that the proposed development would indeed attract birds and if so whether they would pose a hazard given any mitigation measures that may be taken. An interesting appeal example from 1994 concerned waste infilling of a site near Cardiff airport and a RAF airfield. A major consideration at the inquiry was aviation safety and the increased risk of bird strike incidents. The inspector noted that this was an appropriate and material consideration that needed to be addressed as part of any assessment of a planning application. He noted that waste sites were a major attraction for "opportunistic feeders" such as gulls, starlings and corvids (crows, ravens, rooks, jackdaws, jays, magpies and so forth). Despite the fact that no quantitative risk analysis had been undertaken the inspector was satisfied from the evidence and representations that the proposed development would constitute a very significant hazard to aircraft operations, the results of which could be catastrophic, and he was not satisfied that control methods such as netting would be effective. This decision was the subject of a High Court challenge in Blue Circle Industries plc v Secretary of State for Wales [1996] but the inspector’s decision was upheld.

PPG25 sets out guidance on development and flood risk and subdivides the area of highest risk into three categories:

•    developed areas

•    undeveloped and sparsely developed areas; and

•    functional flood plains.

However, the note gives no guidance on when a sparely developed area might be considered a developed area, or vice versa. Neither is there any advice on whether such descriptions apply to a site under consideration or to the wider area surrounding it. What is your view?

I can find no cases that throw any light on this. The difference between a ‘sparsely developed’ area where the population is thinly scattered and a ‘developed’ area will clearly be a matter of fact and degree and in many circumstances should be self-evident. Can any reader with experience of this matter help?

My client wishes to convert a listed dovecote to holiday accommodation with car parking. The dovecote and its immediate surroundings are a scheduled monument. The planning authority accepts that the use complies with policy and listed building consent is not required for the alterations because the building is scheduled. Although scheduled monument consent has already been granted for a detailed proposal, this was later refused planning permission because of its harm to the integrity of the monument and its setting. Is the authority able to do this and are you aware of any relevant cases? In an appeal, what weight should be attached to the existing consent?

There is no advice on this in PPG16, which sets out guidance on planning and archaeology. In England, applications for scheduled monument consent are made to the Department for Culture, Media and Sport, in accordance with the Ancient Monuments and Archaeological Areas Act 1979. The procedures are governed by the Ancient Monuments (Applications for Scheduled Monument Consent) Regulations 1981. English Heritage is responsible for advising the department on whether consent should be given. Consent does not override the need to also apply for planning permission where needed. A local authority is entitled to refuse such permission in the interests of protecting the monument. However, it seems perverse for an authority to refuse permission where scheduled monument consent has already been granted, since this will already have considered the physical and visual effects of the proposed development on the monument. The only precedent I can find is in a decision from Somerset last year. In that case, consent had been granted for the conservation of a number of Bronze Age cairns. The local authority later issued a split decision on the application, refusing permission for works to some of the cairns because it felt they would harm the appearance of the site and its surroundings and the public appreciation of the archaeology. But the inspector disagreed and allowed the appeal (DCS No. 100038102). Although that decision was silent on the implications of the existing consent, in the situation you describe scheduled monument consent for identical works is a significant material planning consideration that would carry considerable weight on appeal. The Government proposes to unify the listed buildings and scheduled monument consent regimes to bring the latter under local authority control.


While it is difficult to respond definitively without knowing the full facts, the Ancient Monuments and Archaeological Areas Act 1979 contains no reference to "setting". Scheduled monument consent is only needed for "works" that have a physical impact on the scheduled area. In theory, it is therefore possible for proposed works to a monument to be given consent but for an authority to quite properly refuse permission for the proposal if it would adversely affect its setting. If a scheme is entirely outside the scheduled area, there will be no need for consent and thus no application in relation to which setting could be an issue. There could also be instances where works proposed in one part of a scheduled area would have a visual impact on another part, such as in the case of an upstanding ruin where the boundary is widely drawn to include open land around it. Works proposed in a scheduled open area might need consent because technically they are works to the monument and the issue may be partly or wholly to do with their visual impact on the monument. The word "setting" may be used loosely in this context. This is not strictly a setting issue because the works and the consent application relate to the scheduled monument itself rather than to its setting. In the case cited by the questioner, I am unsure what the authority had in mind in referring to "harm to the integrity of the monument" and whether that is a separate objection from that relating to setting. English Heritage usually tries to work with both the local authority and the applicant to try and avoid conflicting decisions on applications for scheduled monument consent and planning permission.


Although the 1979 Act refers only to works to the monument itself, the Secretary of State has previously taken the view in such circumstances that the proper test extends beyond the mere physical impact of the proposed development on the monument to include issues of need and visual impact.

My authority uses a standard contamination condition that repeats example C in Annex 2 of PPS23. Our environmental health officers argue that the last sentence of sub-paragraph (c) of the condition allows the authority to insist that developers must render harmless any contamination that might have migrated into the surrounding environment as well as on the site itself. In a recent case, they asked for monitoring tubes to be placed in nearby private gardens and for remediation to be carried out on land outside the applicant's ownership if tests indicated that it was necessary. Not surprisingly, the developer refused to do this. This requirement seems to fly in the face of the advice in Circular 11/95. What is your view?

PPS23 points out that the contents of Annex 2 are not model conditions but merely examples of conditions used by some planning authorities. Sub-paragraph (c) to the condition cited stipulates that remediation works "shall be of such a nature as to render harmless the identified contamination given the proposed end use of the site and surrounding environment, including any controlled water". I agree that the latter half of this sentence is unclear. However, paragraph 2.49 of PPS23 explains that in determining applications, authorities should satisfy themselves that significant pollutant linkages will be broken by removing the source, blocking the pathway or removing receptors and that the development will not create new pollutant linkages by changing or creating exposure pathways. Paragraph 2.51 adds that the standard of remediation to be achieved through the grant of permission for development, including land remediation activities, is the removal of unacceptable risk and making the site suitable for its new use, "including the removal of existing pollutant linkages". This suggests that remediation should be limited to the application site itself, including preventing the migration of contaminants into adjoining land or waters. But while the PPS goes on to say that in some cases it may be necessary to require subsequent monitoring of pollutant linkages and risk, I cannot find any requirement for developers to remediate land beyond their control. This would seem unreasonable. I agree that the interpretation your environmental health officers have placed on this matter would be contrary to advice in Circular 11/95.

A proposed flood alleviation scheme comprising walls, embankments and other works would allow adjoining areas to flood naturally for a few days during such an event. Should the application site boundary include both the physical works themselves and the other areas that will flood? The latter could be said to have been legitimised through formal inclusion in the scheme, even though a material change of use might not arise as a result of temporary inundation. Alternatively, should the application be restricted to the physical works?

It is difficult to see the justification for including areas of land that might be temporarily flooded within an application site, since this would not constitute development for which permission is required. However, where land would be surrounded by earthworks or other engineering operations in order to create a flood storage area, it seems reasonable that the whole of the area should be included in the application. General guidance on development and flood risk is given in PPG25.

I am involved in a housing scheme that is likely to be affected by coastal erosion in the next 60 years. The architects have proposed relocatable dwellings that could be easily dismantled and removed. Initially I thought this idea would not satisfy certainty tests, but am now reconsidering. Could this development be acceptable in planning terms, particularly if the houses are tagged and a Sec. 106 agreement entered into to ensure that they are relocated at the appropriate time?

It is difficult to envisage how such an idea would work in practice because it is hard to foresee what particular event would trigger the need for the houses to be relocated and the implications for the future pattern of development in the area. Such a proposal would require the developer to identify at the outset the ultimate position of the re-sited dwellings and for the planning authority to determine at the application stage that this would be acceptable. Yet such action may not be required for several decades, the timescales and action required for individual dwellings may vary and it is impossible to anticipate the policies or circumstances that might prevail in the longer term. This is not a scenario that is postulated in PPG14 on development on unstable land or one that I have ever encountered. In view of the uncertainties and the possibility that such a proposal could result in piecemeal development, I share your initial concerns. I do not think it likely that any authority would be willing to accept such a proposition.

I am involved with a small environmental organization concerned about plans to develop a heavily polluted site, where pollutants have already started leaking out. Applications to develop the land have not made it clear how this would be effectively remedied. The local planning committee have agreed to grant outline permission, but has left its officers to decide what conditions should be attached. Is this a proper procedure for a complicated and controversial application? JP.

It is quite common practice for officers to be delegated the authority to formulate appropriate detailed conditions after approval of a development by committee. In the case you describe I assume that this course of action was the result of a formal resolution, based on an officer’s report which would have already indicated the areas of concern that conditions should cover were the development to be approved. I do not see how this procedure could be challenged as improper, if done transparently. However, if council members became aware of public concern about the nature of any conditions which may be imposed by officers, they do have the power to recover the matter before a decision letter has been issued. GH.

In 2003 my client received permission for eight holiday chalets, where the application had included a Flood Risk Assessment (FRA). A further application was made in 2007 which sought to increase the number of chalets to 14 by altering a condition on the original permission which limited the number to eight. One of the reasons for refusal was that no new FRA had been supplied. Should I have provided a new FRA when all I was doing was seeking to vary a condition? AH.

PPS25 Development and Flood Risk requires FRAs to be submitted in support of applications where flood risk is an issue. PPS25 does not specifically state whether a further FRA would be needed in your particular circumstances, as its guidance is general. My advice would be to approach the Council to ask why a further FRA is required. It could be because circumstances have changed around the site so that flood risks are perceived to have increased, perhaps as the result of a recent flood. Other reasons may be because an extra 6 chalets would increase run-off, or almost doubling the number of chalets would increase the number of occupants in potential danger. Depending on their response, it would probably be worthwhile having a further FRA prepared and resubmitting your application, possibly making further changes to overcome other reasons for refusal. That reduces the distance between the parties and maximises your chances of getting permission from the local authority or on appeal. JH.

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