In August 2020, Natural England wrote to Local Planning Authorities (LPA) setting out concerns over the increase of phosphates into the eco system due to new developments. 

This follows on from the previous advice given by Natural England in relation to nitrates in the Solent area which significantly delayed the grant of planning permission.

Developers are now watching closely to find out how the LPA will respond to this guidance and how this will impact any proposed development. We set out what this means for registered providers (RPs) below.

The issue

The guidance stems from a ruling from the Court of Justice of the European Union which set out that more certainty is required in the mitigation of increased nutrients into sensitive receptors resulting from particular ‘projects’.

Higher scrutiny and necessary limitations would be placed on activities which would result in a high nutrient load in Special Protection Areas (SPA), Special Areas of Conservation (SAC) and Sites designated under the Ramsar Convention.

Following from this ruling, Natural England has identified concerns about excessive growths of algae in watercourses caused by excessive phosphates as a result of additional development which in turn affects the plant and wildlife growth in these areas.

The impact on development

Natural England advises that the impact of phosphates to a protected site should be considered with the appropriate assessment and with regard to their conservation objectives. The LPA should adopt a “nutrient neutral” approach and only grant permission for development where this would be achieved.

The types of development highlighted by Natural England include, additional residential units (including tourist and student accommodation) and commercial development which result in an increase in loading from the development’s waste water treatment works.

Somerset Levels and Moors

The Somerset Levels and Moors are a designated SPA and Ramsar Site. It has been identified that this area is at risk of excessive phosphates seeping into the watercourse and negatively affecting the ecosystem. Whilst improvements are being undertaken to sewage treatment works, the pollution rate is not enough to mitigate the harm and restore the Somerset Levels and Moors to a suitable condition.

This issue is applicable to any development which can directly or indirectly affect a watercourse near a Ramsar Site and it is likely that this will gain prominence with 175 current Ramsar Sites in the UK.


There is currently no formalised method of calculation for phosphorous output. Somerset West and Taunton Council have been developing a calculator which is expected to be published in early 2021. Then developers will need to be able to show that the phosphorus levels can be mitigated in order to secure planning permission.

Some ways in which developers could provide mitigation, that may be accepted by the LPA and NE include:

  • an on-site obligation to include treatment works within the development to neutralise the phosphorus output and to bring the phosphate level to zero, in line with Natural England guidance, and to ensure no chemical by-products are created in the process.
  • purchasing land that has an existing phosphorus output and converting this into wetland, thereby cancelling out the output caused by the development. This would need to be maintained and managed by an expert body.
  • purchasing credits similar to the Solent nitrate mitigation regime, whereby a third party would deliver the mitigation measures with developers buying credits into the scheme. The benefit of this method is that a developer does not have to manage any type of mitigation themselves or reconfigure a site to accommodate mitigation measures.

The overwhelming conclusion to any mitigation measure is that it is likely to have a significant cost implication to the development. There are also a limited pool of technical professionals who have the expertise to advise on this.

What does this mean for registered providers?

It can be expected that a planning application for any development within a designated site is likely to be affected.

  • A Habitats Regulation Assessment must be undertaken in consultation with Natural England, who will be unlikely to support an application unless it can be satisfied that the proposed development will not have an adverse effect on the nutrient level in a protected area.
  • Any mitigation measures would then be secured by planning condition to ensure any measures proposed are implemented, or where appropriate, a Section 106 Agreement will be drafted to secure the payment of monies or the regulation in respect of any land required to mitigate harm of the development.

When acquiring units from a developer, it is important to find out whether any mitigation measures are required as part of the planning permission and if so, whether they have been implemented by the developer prior to handover and discharged by the LPA. The management responsibility of any on-site mitigation needs to be clearly defined including the costs of any ongoing maintenance.

Where the site is being acquired for a land-led scheme, it is important to undertake thorough due diligence to establish whether phosphate mitigation will be required. It is advisable to seek pre-application advice from the LPA. If the site is being purchased with the benefit of outline planning permission, care should be taken to scrutinise any conditions or policy requirements which could pose a difficulty in obtaining reserved matters approval.


Phosphates will be a growing issue going forward when considering development near a designated site. This could have a significant cost implication and delay to planning applications. We would therefore advise that our clients take this into account and take appropriate technical advice and due diligence prior to making a contractual commitment.

If you have any queries around what's discussed in this article, and the impact on your organisation, please speak to Suzanne Smith or Jennifer Eng to find out more about how Capsticks can help.