Nutrient Reduction Programme

Nutrient Reduction Programme

How the programme works

The impact of nitrogen inputs in the Solent has caused harm to the coastal environment and the issue has led to the suspension of the granting of planning permissions in south Hampshire until a solution can be found. The Trust is keen to find a nature-based solution and we have therefore launched our Nutrient Reduction Programme.  

The Trust aims to acquire land suitable to facilitate a reduction in nitrogen entering the Solent across a number of catchments in order to provide options for offset for all local authority areas. Our programme will not just reach nutrient neutrality but aims to lead to a reduction in nitrates in the Solent. 

Anyone who wishes to enter the Trust programme is asked to complete and submit an Expression of Interest form (see below).  Completion of the form does not commit you to entering the programme or to the Trust to selling nitrate credits to you however, it does assist the Trust in understanding how much capacity is needed and in which catchment. Please review the FAQs below before getting in touch.

More information:

NB. The Trust cannot work out the nitrogen load for developers, you will need to agree this with Natural England or your Local Planning Authority before submitting an Expression of Interest Form. 

The Trust has established a number of tests that we require developments to comply with before we will sell nitrate credits to them (see below).  We will contact the Planning Officer to confirm that the tests have been met as part of our internal processes 

The Trust will typically sell nitrate credits on a first-come-first-serve basis, although other factors will also influence which applications are accepted and in which order (see next section).  As there is currently limited capacity it would be useful to register your interest as soon as possible. 

Once we have secured mitigation sites and agreed the capacity of the site with Natural England the Trust will be able to finalise the cost per kg of nitrogen offset. In addition to the cost per kg, which we currently estimate will be in the region of £2,500 - £3,000 per kg, excluding VAT, an administration fee of £1,000 will be applied for each transaction (not each kg of nitrogen) plus legal fees.  We will aim to keep legal fees as low as possible.  Nitrate credits will be sold to developers either through a conditional contract for larger developments contingent on the granting of planning permission, with payment due shortly after planning permission has been granted or by a simple sale for smaller developments, usually those below 5kg. 

The Trust will aim to enter into agreements with all the Local Planning Authorities which will reduce the need for individual developers to enter into separate nitrate Section 106 agreements. 

The Trust is in negotiation to purchase of a number of sites, however, we cannot guarantee that we will have offsetting options available for all development locations available at a given time and subject to our own screening process. 

If you would like to discuss the programme, please email with your query. 

Our Tests

When supplying nitrogen offset credits to a developer for a specific development, Hampshire & Isle of Wight Wildlife Trust upholds widely accepted principles to ensure the protection and enhancement of biodiversity. These principles are underpinned by legislation and policy and apply both to the footprint of the development and any offsite impacts.  

We have set out below a series of tests which each development must fulfil, in addition to the nitrogen offset, in order to be deemed acceptable to the Trust and therefore supplied with nitrogen credits to enable development(s) against which they are linked. 

View our series of test:

  1. The development should be in an adopted Local Plan or be approved by the planning officer for the relevant local authority. Under certain circumstances, windfall developments and those outside of an adopted Local Plan will be deemed acceptable where they ensure full compliance with the other criteria outlined below. 
  1. The development should not carry an objection from Natural England or the local authority ecologist or the Wildlife Trust, and not lead to loss of irreplaceable biodiversity.  
  1. The development should demonstrate compliance with ecological mitigation required by the statutory bodies especially with respect to designated sites (e.g. water pollution and provision of sites used by coastal birds – see note below).  
  1. If necessary, and in compliance with 3), the development must make contributions to mitigation schemes such as Bird Aware Solent and New Forest mitigation schemes or have an equivalent or better scheme in place. 
  1. Where there is over demand for credits, preference will be given to developments which demonstrate biodiversity net gain, delivery of the Local Ecological Network or adoption of the Building with Nature green infrastructure principles. 

Of relevance to 3) in southern Hampshire and the north of the Isle of Wight is any impacts, direct or indirect, on the network of sites used by coastal birds which are features of the Solent Special Protection Area. These sites have been assessed and mapped in the Solent Waders & Brent Goose Strategy3 and all sites which are classed as ‘Core’ are not deemed appropriate for development under any circumstances. We expect the mitigation guidelines within this strategy to be followed. 

NB. 5) Building with Nature 

Expression of Interest 

Please review the FAQs below before getting in touch. Please complete the webform below to submit your expression of interest in Hampshire & Isle of Wight Wildlife Trust's nutrient mitigation scheme.

Please note, completion of the form does not legally commit the sender to any contractual arrangement or commitment to purchase nitrate credits, nor does it commit the Trust to selling credits to you. 

Additional or updated information can be submitted through this form by providing the unique reference number you were issued with upon initial completion. If completing the form for the first time, please make a note of your unique reference number for making future changes or when communicating with us. Please direct any questions to

Please fill in the Expression of Interest Form below

Please enter a 6 or 10 figure grid reference with no spaces, e.g. SU5238113505; use to get this if not known.

One file only.
100 MB limit.
Allowed types: zip, pdf.

A planning reference is essential for our screening process and we cannot issue contracts for nitrates credits without it, so please update your EOI as soon as a planning reference has been assigned. (See also: FAQs).

15. Is the planning application a phase of a larger development?
17. Has the nitrogen budget been accepted by the LPA?

For septic tanks and PTP please seek confirmation of this from your LPA or NE - you will not be able to confirm your nitrate requirements without this information. See also: FAQs

22. Are you confident the development will comply with the Wildlife Trust's Tests (details above)?
23. Are there any other outstanding Grampian conditions which need to be satisfied?
25. Are you interested in potentially doing more to help wildlife and the environment through working with the Wildlife Trust in other areas? (By ticking below this will simply prompt one of the team to get in touch and does not commit you to anything).

* Q. 19 - you may wish to purchase additional nitrate credits which would help towards reducing pollution levels in the Solent. If so, please tick the "nitrate reduction" option in Question 25 and we will contact you to discuss further. If TBC, please note we will not be able to process credits sales or advise on capacity until this is known.


Can you sell me credits / when can I buy credits?

The sale of credits is subject to your planning application passing our tests and our ecological screening process, and being located within an area where we have a mitigation option available (see below for more on this). Our current site is now at capacity. A second site, covering developments within the Local Planning Authorities in southeast Hampshire and discharging to Budds Farm or Peel Common wastewater treatment works, or within the Eastern Yar catchment, will be coming online shortly. This is subject to the signing of legal agreements with the relevant local authorities which can take some time. At present, we expect the sale of credits to begin no earlier than mid-September 2021 but this may be delayed by circumstances outside of our control. We will contact you when the sale of credits can begin, subject to your scheme passing our tests and ecological screening process.

I submitted an EOI weeks ago, when will I hear from you?

As above, our current site is at capacity, and we will be in touch when the second site comes online and we are ready to sell credits.

Can I buy credits at the pre-app stage?

If you have submitted an EOI for a pre-application scheme, please be aware we will not be able to process your request until you have a full or outline planning application under consideration with your Local Planning Authority. Your planning application reference number will be required for the legal paperwork and the associated planning documents will need to be reviewed as part of our screening process. However, we’re happy to conduct an initial screen of your proposal to give an informal opinion of whether the scheme is likely to be acceptable; please email to request this. We will need a site boundary and outline of the proposals to do this. Informal opinions will not oblige the Trust to sell credits at a later date: the application will still be assessed fully when submitted to the LPA. Please note that the clearance of sites before ecological surveys can take place is considered bad practice by the Trust and may result in the development failing our screening process.

Can I buy credits for a proposal in the Test & Itchen / Chichester / New Forest /West Wight catchment?

We do not currently have any options for these catchments; however, we are in discussions with landowners in the New Forest and Test Valley. We hope that a new site for the New Forest may be available in late autumn of 2021 but we cannot confirm a date by which credits will be available for sale at this time. Our website will be updated should options in the Test and Itchen or New Forest catchments come online sooner. However, you may wish to explore other options on the Partnership for South Hampshire website:

Why can’t I buy credits to offset a site in a different catchment?

This is governed by the way sediments and nutrients flow around the Solent, which was determined from modelling work carried out by Natural England to better understand this natural process. NE found that the Solent operates as a series of sub-catchments rather than one large catchment. In order to mitigate effectively for discharges to the Solent, mitigation sites for offsetting must therefore be located within the same sub-catchment as the wastewater treatment works used for the development. For example, our current site on the Isle of Wight can mitigate for developments in Fareham as this falls under the East Solent Fluvial Catchment, which covers Wastewater Treatment Works at Peel Common and Budds Lane in Hampshire, as well as those discharging to the northeast rivers of the Island. Discharges to Chichester Harbour, on the other hand, fall under a different sub-catchment and would require a mitigation site located in the Chichester area.

You can find more information about this in the document Advice on Achieving Nutrient Neutrality v5 June, p26-27 (the link will take you directly to a pdf on the Partnership for South Hampshire website).

How much will it cost to purchase credits?

The cost of each credit depends to a certain extent on the cost of securing the mitigation land. We aim to keep costs to a minimum and estimate that we will be charging between £2500 and £3000 per kg. These costs exclude the legal (£1500-£3500 per transaction) and administration fee (£1000 per transaction), and are exclusive of VAT

Can you work out how much nitrate mitigation I need for my development?

The Trust does not carry out assessments of nitrate requirements for developers; we feel this might represent a conflict of interest, given our role in selling the mitigation credits. There are a number of planning agents and consultants who are offering these services, though, and can provide you with the information you require.

Why should I choose your scheme over others?

The Trust’s scheme has been up and running since the autumn of 2020 and we have a well-developed and proven methodology and processes in place. Our approach has been signed off by Natural England and has been validated by Fareham Borough Council. To date our scheme has seen well over 50 planning permissions granted.

Crucially, the Trust’s scheme puts wildlife recovery at the centre of our approach. Not only are we aiming to create a series of incredible nature reserves at the mitigation sites, but our scheme also aims to reduce nitrates in the Solent and not merely aim for neutrality. We therefore remove an additional 5% of nitrates over and above the number we sell to you with the aim of helping the Solent recover.

What about Biodiversity Net Gain, carbon mitigation, etc.?

We are examining the opportunity to stack benefits on mitigation land with biodiversity and carbon mitigation options being considered. Working in these additional facets does increase the complexity of the scheme but we feel it does present opportunity to add additional benefits and reduce costs for the developers. We will be further developing the options in these areas over coming months. If you would like to discuss our BNG offer please email your interest to in the first instance.

My scheme uses a septic tank/PTP – can I buy credits?

You will first need to get formal confirmation from either the Local Planning Authority or Natural England as to which catchment they feel it comes under – we can’t make the judgement on this. Once this is known, we can confirm whether your proposal can be mitigated by one of our sites in the same way as proposals discharging to mains systems (See: Why can’t I buy credits to offset a site in a different catchment?, and: Can you sell me credits / when can I buy credits?).

Can I amend the name / make changes to the number of credits after I have purchased them?

We recognise that circumstances change over the course of a planning application but please make every effort to supply the correct information up front. Changes to the legal entity details for credit sales, planning application reference numbers, and/or reducing the number of credits purchased can generally be accommodated but will attract an administrative fee of £150+VAT per amendment (and sometimes further legal fees). Increasing the amount of nitrate mitigation required may be possible but will be dependent on whether sufficient capacity remains at our mitigation site(s). This will also attract further administrative and legal fees. Please get in touch via the address as soon as possible if you need to make changes to your application for credits.