Planning Approach to Hatfield Forest National Nature Reserve and Site of Special Scientific Interest
These designations mean that local planning authorities must protect it and assess whether development will harm the Forest and take advice from Natural England on proposals which might damage it.
Natural England wrote to the Council in April 2025 setting out that the habitats and species which make the Forest special were being harmed by visitors and that this would be made worse by future developments nearby.
They have developed a programme of mitigation work to prevent the situation getting worse. New developments built in the area will need to pay towards implementing them. Larger schemes (approximately 50+ residential units) will also need to provide or pay for sustainable alternative natural green space (SANG).
East Herts District Council will therefore expect all relevant developments to pay this tariff (£538.35 per net additional dwelling) within the area which is affecting Hatfield Forest. Other fees and charges will also apply. You can check if your site is within the area here (click on the small arrow top right and tick the box next to Hatfield Forest Zone of Influence).
For minor schemes (proposing 1-9 homes) this should be done by completing the Unilateral Undertaking legal agreement at the bottom of this page and submitting it with land ownership information and a Fee Undertaking with planning applications. For major schemes which already need a s106 agreement this clause and requirements for SANG will be included in the wider legal agreement.
Background
Hatfield Forest is the best example of a surviving Royal Hunting Forest in Britain and covers an area of approximately 400 hectares. It is home to over 3,500 species of wildlife and some trees over 1000 years old.
It is designated as a Site of Special Scientific Interest and a National Nature Reserve to ensure that these species and habitats are protected. At the same time it is a valuable resource for the community to spend time in nature and use open space.
As such, the need for people to access and use the space needs to be balanced against making sure that harm isn’t caused to the special character of the Forest. You can find out more about the forest here.
Planning policy and guidance
The Countryside and Wildlife Act 1981 (as amended) places a legal duty on the Council to consider whether proposals would cause harm to SSSIs and, where they might, to consult Natural England and not allow proposals unless there is an overriding public interest. More information on this is available here. In planning terms, the East Herts District Plan 2018 sets out that SSSIs and NNRs should be given a very high level of protection from harm from development. This is also set out in the National Planning Policy Framework. This means that generally proposals which harm these sites will be found to be unacceptable unless there are clear reasons not to.
Advice from Natural England
Natural England have been working with the National Trust to ensure that the Forest is suitably protected. They have found that the special characteristics of the site are being harmed by visitor activities and that future visitors from new developments could make this worse. To stop this harm, they have developed some projects which they intend to implement called a Strategic Access Management and Maintenance strategy (SAMM). They have also identified when alternative new open space needs to be provided (Sustainable Alternative Natural Greenspace(SANG)) with developments. A copy of the strategy is available below.
Natural England has also worked with East Herts District Council and other affected Councils to identify potential future visitor numbers and how the nature conservation projects could be funded. They wrote to the Council in April 2025 advising that new developments resulting in at least 1 additional new home within an 11.1km distance of Hatfield Forest should pay a contribution towards the SAMM works and that larger schemes (generally of over 50units) would need to provide SANG. A copy is available below.
In East Herts the tariff cost of SAMM is £538.35 per net additional dwelling. This applies to all net increases in dwellings falling within Use Class C3 and also applies to proposals within Use Classes C1, C2, C4 and some sui generis uses. Potential developers are recommended to discuss proposals with Natural England before submitting a planning application for potentially affected non-C3 Use Class schemes, as well as with the East Herts through our pre-application advice.
Consideration of individual planning applications
Having received this advice East Herts will be applying it to all applications creating net additional residential units within 11.1km of Hatfield Forest and will expect developments to mitigate their impact on the Forest by paying the SAMM tariff and where necessary (generally on larger schemes of 50+ new dwellings) providing SANG. This also applies to all applications which have been submitted but not decided.
The SAMM tariff will need to be secured through a legal agreement, along with a small amount of money to meet the Council’s costs in monitoring that the agreement has been complied with. If your development is likely to have a legal agreement anyway (generally on applications for more than 10 residential units) then this would be included in that. More information on legal agreements can be found here.
For smaller applications it is likely that this will be the only item which needs to be secured in a legal agreement. A template Unilateral Undertaking (legal agreement) is included below. This should be completed and submitted with your planning application.
As set out in the Unilateral Undertaking template, the costs comprise of the SAMM tariff and monitoring costs as set out below:
- For 1 -2 net additional dwellings £200
- For 3-5 net additional dwellings £400
- For 5 dwellings + £1200
When you submit your planning application you will need to submit a completed Unilateral Undertaking with it. Planning legal agreements affect the land to which the application relates and so are registered as a local land charge (so if the land is sold, the new owner needs to meet the requirements of the legal agreement). Therefore, anyone with a legal interest in the land needs to sign the legal agreement, including, potentially, any mortgagee or sometimes people who any part of the land is leased to. When you submit your planning application you will need to submit up-to-date official copies of the registered title(s) for the land to show that all of the right people have signed the agreement.
When we receive the planning application we will check that the Unilateral Undertaking has been completed properly and the right information provided. This will be done whilst we process the application. You will need to meet our costs in doing this and so need to complete an undertaking to meet these fees, which are generally up to £500. This can be done on our Legal Undertaking form.
More details on what needs to be submitted with a planning application can be found here. Copies of the Unilateral Undertaking, Legal Undertaking form and advice from Natural England are at the bottom of this page.
