Green belts were created after the Second World War. The Town and Country Planning Act 1947 (the same piece of legislation that first introduced permitted development rights) allowed local authorities to designate doughnut-shaped tracts of land around their settlements as areas that should not be developed.
The purpose of green belt land is to prevent towns from sprawling outwards and eventually merging into each other. Green belts encourage development to take place within the town boundaries. The key quality of green belts is their openness.
The general population has a fear that uncontrolled development will eventually pave over the countryside. As a result, and without reflecting on it to any great extent, voters are keen to preserve the green belt and politicians are generally loathe to interfere with it, despite a desperate need, nationwide, to build more houses.
The NPPF (the government’s national planning policy document) says that new developments in the green belt must not be allowed, with limited exceptions. One exception is building “infill dwellings” in existing villages. An infill dwelling is essentially a house built to occupy a gap in the streetscene. Another is the replacement of existing buildings with a new development, where the new development is not much larger than the existing and does not have a greater impact on the openness of the green belt. This allows the demolition of existing houses and their replacement with new, slightly larger, dwellings, or sometimes the demolition of other buildings (such as outbuildings, or commercial buildings) in favour of new dwellings of a similar height and footprint.
People are often surprised to hear that limits on new development in the green belt also apply to householder extensions. The extension of a house is only allowed where the extension is not “disproportionate” to the original dwelling. In other words, if your house is in the green belt, you may extend it only in a modest or limited way. Crucially, all extensions carried out since the house was built must be taken into account so, if you have bought a house that was previously extended in the 1980s or 1990s for example, it is possible that you will not be able to extend it any further. Not all buyers are aware of this when they buy a home and it can be a source of great frustration.
The NPPF does not explain what it means by “disproportionate”. In the planning policy hierarchy, national policies set out a general strategic direction and it is up to local councils to add flesh to the bones through their own development plans. Some councils don’t really define “disproportionate” either and it is down to individual planners to make a judgement on a case-by-case basis. That is clearly not good planning – how are applicants and their architects supposed to come up with an acceptable scheme with no direction whatsoever?
Most councils have some kind of specific guidance. It is common, for example, for councils to have a policy that says something like: “cumulative extensions (i.e. all previous extensions plus the development proposed) should not increase the floor area (or volume) of the original house by more than 40 percent.”
Clearly, if you exceed this policy limit, you will need to justify it. For something like this, you will need the help of a planning consultant. When I advise clients on extensions in the green belt, I first work with their designer to establish how much the house has been extended in the past. Sometimes we discover that the house has already been extended beyond the percentage limit set out in policy. I check how dated the policy is and whether it is clear and unambiguously worded. I look at recent decisions in the council area for other extensions in the green belt to see how case officers have made their assessments (always read the officer’s report!) and I check appeal decisions to see whether the council’s refusals are standing up at appeal. If the policy is badly worded or out of date, if the council’s own case officers don’t pay much attention to it when making assessments or if they often refuse permission but then lose at appeal, I will generally advise the client to submit an application in contravention of the policy with a strategy of persuading the case officer to grant approval or of winning a subsequent appeal.
Apart from the simple mechanics of how far the extension increases the volume or floor area of the house, decision-makers will assess the extent to which a development reduces openness – the key characteristic of the green belt. Basement extensions, infill extensions to the rear and extensions that make use of the existing volume in the roof space, for example, all reduce openness less than a two-storey side extension might do, for example. The character of the surrounding green belt also matters.
Much of the green belt is not very open at all – it “washes over” small settlements where, in some cases, the houses are so densely packed, the immediate area resembles the suburbs of a large town. In cases like that, it may be easier to persuade a case officer or appeal inspector that the proposed development will not reduce the openness of the surrounding green belt.
It is worth noting that houses in the green belt have the same permitted development rights as houses that aren’t in a green belt. So, if you are unable to extend your house through a grant of planning permission (because your house has been extended in the past or the council considers your proposed extensions disproportionate to the original building), you should explore what can be built under your permitted development rights.
We sometimes apply for Certificates of Lawfulness on behalf of clients to establish that they can add a certain quantum of floorspace under permitted development and then use this fallback position as a basis of negotiations with the planners to try and achieve the development the clients really want. As I will explain later in this chapter, fallback positions are a material consideration and if planners believe that the applicants will build out the alternative proposal, they may grant permission for something similar that does not cause greater harm in planning terms.
If you are planning to extend in the green belt and would like some advice, consider the Ask Martin service. If you have been refused planning permission and are considering a planning appeal, contact Just Planning for advice.
