Planning: the conversion conundrum

Planning: the conversion conundrum

The recent case of Hibbitt v Secretary of State for Communities and Local Government (1) Rushcliffe Borough Council (2) [2016] provides some much needed guidance from the High Court on the interpretation of the Class Q permitted development rules, with judicial consideration of the meaning of ‘conversion’.

This case concerned an appeal from the decision of a Planning Inspector who confirmed the decision of the Local Planning Authority (LPA) refusing prior approval to the proposed development.

The appeal involved a basic, open sided, steel framed cattle building measuring 30m x 8m.

Class Q permitted development allows a change of use from agricultural to residential and the associated operations reasonably necessary to convert an agricultural building to a residential one. Class Q only permits the installation or replacement of windows, doors, roofs or exterior walls or connection of relevant services to the extent reasonably necessary to allow the building to function as a dwelling.
National planning policy guidance also has to be taken into account.  There are two relevant points to extract from the guidance. First, Class Q assumes the building is capable of functioning as a dwelling.

In addition, construction of new structural elements is not intended, so the building must have the structural integrity to cope with the works needed to provide for residential use. Guidance cannot bind the court, but it can be taken into account.

The inspector’s decision

The Inspector started with the premise that development rights described in Part Q relate to conversion of a building.  As such, the building must first be capable of functioning as a dwelling.  The Inspector was satisfied with the applicant’s proposal to use structural infill panels to construct walls and a ceiling within the existing frame of the building.  Further, she said that she had no reason to dispute the applicant’s claim that the frame and foundations of the building were structurally sound enough to enable the dwelling to be constructed using the existing frame.

However, the Inspector refused the appeal as the building would not be capable of functioning as a dwelling without the construction of all four exterior walls which goes well beyond what could reasonably be described as conversion.  Notwithstanding the reuse of six steel uprights as the main structural elements of the building and the retention of the roof, the works described would be so extensive as to comprise rebuilding.  The Inspector therefore concluded that the works necessary to create a dwelling from the structure on the site would not fall within the scope of that permitted under Part Q and accordingly would not be permitted development.

The appellant appealed to the High Court.

High Court decision

The Claimants argued:

  • there is no need to define ‘conversion’ and the process of turning an agricultural building into a house is, by definition, a conversion;
  • the existing building is structurally sound so this is not a rebuild by definition; and
  • the administration of permitted development rights requires certainty which would not be achieved if an assessment of what constitutes conversion and rebuilding had to be considered in each case.

The court rejected these arguments and confirmed the decision of the Inspector for the following reasons:

  • The concept of conversion is set out in the overarching provisions of Class Q itself and not in Class Q1 which sets out what is not permitted
  • Conversion is a different concept to a rebuild, with the latter not being solely restricted to work carried out on a bare site. The test is one of substance as to whether the works reasonably go beyond conversion
  • There is no need to define rebuild and conversion within the legislation because it is being applied by an expert audience, who know what these concepts mean and how to apply them in a planning context
  • Permitted development must be construed narrowly as it is not intended to be a shortcut for complex cases.  This is a fast track system for genuine conversion of agricultural buildings and if extensive rebuilding is required, then that is a case for full planning permission and not permitted development rights.  An appropriate balance must be struck between the full planning regime and the fast track of permitted development;
  • Part Q does not allow for the construction of new structural elements and that again shows a distinction between rebuild and conversion;
  • Having an agricultural building as a starting point does not automatically make it a conversion and not a rebuild.  The conversion of a skeletal agricultural building into a dwelling house might involve a great deal of work, which is more akin to a rebuild than a conversion.
  • A building might require extensive works to convert it into a dwelling house, but that does not necessarily disqualify it as a rebuild.  The extent of the works would clearly be relevant, but it is not going to be conclusive.

The Inspector was not challenged on her factual finding that the work constituted a rebuild and not a conversion.  This was an appeal on a point of law and it seems to be accepted that the distinction between a rebuild and a conversion is a legitimate planning judgment that is to be made in each case.


This decision seems to imply that skeletal and minimalist agricultural buildings are going to struggle to get through under Class Q permitted development rights and may require a full planning application.

Anecdotal evidence would suggest varying approaches from different LPA’s across the country. This indicates a lack of consistency in dealing
with such applications. Clearly some success has been achieved in terms of the conversion of very functional agricultural buildings, as opposed to the more traditional stone or brick buildings.  LPA’s may now rely on this High Court decision to apply policy in a much more consistent and rigorous manner.

For more information please contact Ben Sharples, Partner in the Agriculture team on or 0117 906 9303.

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