How Does Local Planning Policy Differ Between Councils? A Planning Officer Explains

Every planning authority has the power to set specific guidelines and restrictions over development in its area. Planning consultant Martin Gaine looks at how this can affect your project

Martin Gaine

Planning policies are the foundation of the whole planning system: if you want to know your chances of getting permission for a new development, your first step is to look up the relevant policies. But how do you work out which ones are relevant to you? National policy tends to be more strategic and high-level, while those at local council level are typically more detailed (and more useful).

To add some extra complications, there are often big differences between policies in different councils. In extreme cases, a development may be possible on one street but not on the next street over, because they fall under different authorities.

In this article, I will explain how things change from national to local level and between individual areas, and how to determine which policies affect you.

How does the planning system hierarchy work in the UK?

Let’s start at the top of the planning system: in England, there is a single document that provides the highest-level strategic policies. It is called the National Planning Policy Framework (NPPF). It’s worth a read (don’t worry, it is only 82 pages long), especially if you want a better understanding of how the planning system as a whole operates. There are slight differences in Scotland, Wales and Northern Ireland, but each has similar national policy documents.

Most areas in England no longer have regional planning policies (the London Plan, covering the 32 London boroughs, is an exception). There are, however, moves afoot to introduce a new layer of regional planning to coordinate things like housing supply.

How Does Local Planning Policy Differ Between Councils? A Planning Officer Explains

Dormer windows can significantly change the character of a building and the wider area; some councils are supportive of them, whereas others restrict them to rear elevations. Photo: iStock.com/George Standen

The most useful policies for smaller schemes are those in the Local Plan, which contains the policies adopted by your council to control development. If you are planning a home extension or a new build, this is the place to start. Note that smaller areas, such as individual towns, villages or hamlets, also now have the power to draw up Neighbourhood Plans, with policies relating specifically to their own individual areas.

Finally, councils can introduce additional guidance in the form of supplementary planning documents (SPDs) specific to a certain area or type of development. SPDs often provide specific and detailed guidance on householder extensions and new build homes and are always worth reading when considering a new project.

How to planning policies differ between areas?

Generally speaking, policies at national and regional level set general principles, such as reducing carbon emissions, delivering a minimum number of new homes and discouraging new development in the countryside or the green belt. Local policies then explain how this policy direction affects you in practice.

The NPPF states that new homes should preferably be constructed within the boundaries of existing towns and villages, for instance, but it is individual council Local Plans that set those boundaries.

The NPPF says that extensions to houses in the green belt (basically a buffer zone between settlements and the countryside) should not be disproportionate. But it is local council policies that specify what is considered disproportionate in their specific area. A typical rule you could come across might be that you can increase the size of the house by no more than, say, 40%.

Planning policies in towns such as Bath place significant restrictions on design and materials usage, to protect the area’s heritage status. Photo: iStock.com/Thomas Faull

Another principle outlined in the NPPF is that new development must preserve highway safety. But Local Plans detail specific parking standards, such as how many spaces should be provided for a new home in certain areas. In urban zones, some councils set maximum car parking standards or require that developments be entirely car free. In suburban and rural areas, local authorities still set out minimum car parking standards, to ensure developments provide for the requirements of future users.

Some national policies are generic (and pretty boring) and tell you very little about what you need to do to get planning permission. It is obvious that new buildings need to represent good design and protect your neighbours from overlooking or overshadowing. Some requirements are so vague as to be meaningless: how is your self build project supposed to “respect and reflect local distinctiveness”?

Local policies and guidance provide the all-important detail. Some are quite prescriptive. Examples might include: dormers are not allowed on the front elevation of houses; new homes should not be built in the rear gardens of existing houses; houses may not be converted into flats; or new homes must provide garden areas of a certain minimum size.

CASE STUDY How do these two local planning authorities differ?

Neighbouring authorities often have diverging planning policies, which can lead to confusing differences in terms of what’s allowed and what’s not, sometimes even on the next street over. Using the London Borough of Barnet and neighbouring Hertsmere Borough Council as our guinea pigs, here’s an example of how diverse policy can be.

	London Borough of Barnet	Hertsmere Borough Council
Local Plan document	Local Plan (2025)	Core Strategy (2013); Site Allocations and Development Management Policies (2016)
Supplementary planning guidance	Residential Design Guidance (2016)	Planning and Design Guide (2006)
Flat conversions policy	Flat conversions not allowed on streets characterised by family housing	Flat conversions not allowed where there would be more than 1 in 5 conversions in a defined row of houses
Minimum garden areas	A minimum of 5m² for one- to two-person dwellings, plus 1m2 for each additional occupant	Houses: minimum of 40m2 for a one-bed, up to 100m² for a five-bed Flats: 20m² for a one-bed, plus 10m² for each additional bedroom
Self build	The council expresses support for self builds, as long as other policies are met	No reference to self build in policy
Homeowner extensions	Side extensions: should not be more than half the width of the main house First-floor side extensions: should be set back 1m from the front elevation Rear extensions: no more than 4m deep Dormers: should not exceed half the width or depth of the roof slope	Side extensions: should have a width significantly less than the main house, and be set back 1m from the front, with a 1m-2m gap to side boundary Rear extensions: may be up to 3.35 metres deep. Dormers: should be small and not exceed 60% of roofslope
Self build	Between 0 and 1.5 spaces per dwelling, depending on accessibility	Minimum of 1.5 spaces per one-bedroom unit and 5 spaces per six-bedroom unit

Different planning authorities have different priorities

The differences in policy between council areas reflect local pressures or preoccupations. The Royal Borough of Kensington and Chelsea has strict rules on combining several homes into one and on the construction of double-storey basements, for instance, neither of which are particularly big issues in the rest of the country.

Whereas most councils only require affordable housing contributions for proposals that create more than 10 new homes, Reading Borough Council stands out as an exception. It requires that even proposals for a single new home make a financial contribution (10% of the development’s value) towards affordable housing, arguing that it is facing a particularly acute shortage of housing.

Locations such as the Lake District have strict restrictions on second homes and local occupancy rates – but modern homes are still built right on the area’s shorelines. Photo: iStock.com/TraceyAPhotos

Design policies are stricter and more specific in sensitive areas. Bath has especially strict design policies protecting its UNESCO World Heritage status, requiring Bath stone and very specific architectural details. Less traditional is bohemian Brighton and Hove, which emphasises creative, innovative design and embraces contemporary architecture.

University towns like Oxford and Northampton have specific policies managing student housing (HMOs) and their concentration. Areas with significant tourist pressure, like the Lake District, typically have second home restrictions and local occupancy requirements.

How to find the relevant local planning policies for your project

It is fair enough to leave the business of reading and understanding planning policies to your architect or planning consultant – they are the experts, after all. But it is not a bad idea to develop a general understanding of the rules that apply in your area. To look up local policies, go to your council’s website (usually councilname.gov.uk), click on “planning” and then “policies”. You will be presented with a list of policy documents of various types. It may take time to work out which are relevant, but don’t be daunted.

Parking requirements are often clearly spelled out in Local Plans and supplementary guidance. Photo: iStock.com/Oliver Hasselluhn

A shortcut to understanding the council’s policies for extensions and other householder developments is to find a similar application that has been decided recently in your area. All planning authorities have a database of applications on their websites, and you can search by keyword or generate a list of all submissions decided in recent weeks.

If you identify an application that looks similar to what you are proposing, click through the associated documents and look for the officer’s report (sometimes known as the delegated report). Prepared by the council’s case officer, this describes the site and proposal, then assesses it in light of applicable policy. Look through several different schemes to see what issues reappear so that, if necessary, you can begin to strategise on how to address them.

Martin Gaine

Martin Gaine runs planning consultancy Just Planning. A former case officer, he has experience on both sides of the planning divide and now specialises in helping homeowners win consent at appeal. He is the author of How to Get Planning Permission: An Insider’s Secrets.