The first Environmental Delivery Plan has landed in Norfolk, and the debate it has sparked reaches far beyond East Anglia. It covers nutrient pollution affecting the Norfolk Broads and River Wensum, but it is also the first real-world test of a model the Government intends to roll out nationally, including in the Solent. The concerns raised by ecologists, environmental lawyers, conservation organisations and local Wildlife Trusts cannot be dismissed. If this approach fails nature in Norfolk, it could fail nature everywhere. 

During the passage of the Planning and Infrastructure Bill, The Wildlife Trusts warned that Environmental Delivery Plans could weaken environmental protections and unravel effective mitigation schemes. We feared the Nature Restoration Fund could become a “cash to trash” system, allowing damage to vital habitats now on the promise of restoration somewhere else, sometime later. 

The first draft EDP suggests those warnings were well founded. 

For decades, the test for meeting environmental obligations has been built around a straightforward principle, known as the mitigation hierarchy. First avoid harm. Then reduce it. Finally, compensate for any harm that remains. 

The Planning and Infrastructure Act 2025 established EDPs as a new route for meeting environmental obligations. In practice, the Norfolk EDP moves away from the established mitigation hierarchy. Instead of focusing primarily on reducing the nutrient pollution affecting protected sites, it relies heavily on broader conservation measures intended to deliver a so-called “overall improvement” for nature. 

This matters because nutrient enrichment remains one of the principal pressures affecting many of England's most important wetlands, estuaries and rivers including those in Norfolk and the Solent.  Wider habitat restoration can add value, but it cannot become a substitute for tackling the pressure causing the damage. 

The solution must address the problem  

The principle should be simple: when development creates environmental harm, the solution must address that harm. 

The Norfolk EDP covers already heavily polluted rivers and acknowledges that their protected sites require significant intervention over a long timescale. Yet new housing is still expected to add further pollution. Norfolk Wildlife Trust’s analysis suggests that the measures would offset only around half of the additional phosphorus pollution, with wider nature recovery measures used to help demonstrate an “overall improvement”. 

If excessive nutrients are a major cause of poor condition in a protected river or coastal habitat, reducing those nutrients must be the priority. River restoration, wetland creation and better habitat management may all be valuable, but they are not necessarily substitutes for tackling the pollution itself. Wider landscape restoration should complement targeted action, not replace it. 

An EDP should be a streamlined mechanism for collecting developer contributions to address the identified environmental pressure, not a pot of money for projects with an increasingly distant relationship to the harm caused. The link between impact and action, problem and solution, must not be lost. 

Weaker by design  

The precautionary, polluter-pays and mitigation hierarchy principles have long underpinned environmental decision-making. 

The EDP system creates a parallel legal route in which the strict requirement to prevent harm to protected features can be displaced by a broader promise of “overall improvement”. It changes the question from “How will this development avoid adding to an existing environmental problem?” to “What improvements can be funded so development can proceed?”   

Those approaches are not equivalent. The new route is not only ecologically weaker; it sits uneasily alongside the established legal principles that require harm to be avoided and mitigated before compensation is considered. Strikingly, the Norfolk EDP contains no avoidance conservation measures. 

When does “overall improvement” mean better?  

The Overall Improvement Test was introduced late in the passage of the legislation after sustained opposition to Part 3. 

This last-minute concession is supposed to provide the backstop and safeguard which requires Natural England to demonstrate that an EDP’s conservation measures will materially outweigh the negative effects of the development it covers. But once environmental impact is separated from the action intended to address it, that comparison becomes extremely difficult. 

How can additional pollution entering an already stressed river be robustly compared with benefits from deer management, habitat restoration or action addressing a different ecological pressure? If “overall improvement” is the principal safeguard, the assessment must be transparent, scientifically credible and capable of showing unequivocally that the benefits materially exceed the harm. Anything less asks nature to carry the risk. 

We’re not starting from scratch 

The Solent is not starting from scratch. This is where nutrient neutrality was first tested at scale, and local authorities, conservation organisations, landowners and mitigation providers have spent years developing practical solutions that reduce pollution while enabling development and recovering nature. The result is one of the country’s most mature nutrient mitigation markets. 

Hampshire & Isle of Wight Wildlife Trust has direct evidence of what this approach can achieve. Since 2022, our schemes at Wilder Little Duxmore and Wilder Nunwell have reduced nitrate pollution entering the Solent by around 3.6 tonnes a year, while enabling more than 2,500 homes across over 350 developments. They are also bringing nature back. At Little Duxmore, soil mineral nitrogen fell by 32.6% between 2021 and 2025 and bird numbers almost trebled. At Nunwell, butterfly numbers increased by 117% and earthworm abundance by 66%. 

This is mitigation doing what it should: addressing the pollution caused while securing wider recovery for nature.  The Solent’s experience must now help shape a better national model, not simply protect the system we have here. 

Build on good foundations, don’t undermine them 

A centrally administered levy could destabilise the local market already delivering nutrient reductions, housing and habitat recovery. If the levy is set below the true cost of effective mitigation, developers will be pulled away from proven schemes, existing investment may be stranded, and future projects could become unviable. Yet if the levy fails to attract enough contributions, the EDP may not raise the money needed to deliver its promised improvement. A poorly designed levy could therefore weaken both the existing market and the EDP intended to replace it. 

The ecological risk is equally serious. Long-term nutrient reductions depend on land remaining out of intensive agricultural production and being managed properly for decades. If the financial model supporting that stewardship is undermined, existing gains could be put at risk. Reform must not leave the Solent worse off. 

If Natural England collects developer contributions through a Solent EDP, its first priority should be to secure proven nutrient reductions. This could include purchasing credits from existing providers, funding established land-use changes and agreeing appropriate arrangements to sustain legacy mitigation land. Existing local partnerships and expertise should shape delivery, not be bypassed. 

That would give Government a streamlined collection mechanism while retaining the crucial connection between cause, impact and solution. Wider landscape recovery could then be funded alongside direct nutrient mitigation, not instead of it. 

The stakes for the Solent 

This is not an argument against new homes or landscape-scale restoration.  The question is whether the new system will strengthen the practical mechanisms already reconciling those objectives, or sweep them aside for a centralised model whose ecological and financial case has not been proven. 

For Hampshire and the Isle of Wight, the stakes are high. Our rivers, chalk streams, harbours and the Solent coast are already under enormous pressure.    

Before any Solent EDP is approved, Government should demonstrate that it will outperform the existing system.  Are fewer nutrients reaching the Solent?  Are the causes of unfavourable condition being addressed?  Are protected habitats recovering?  Are existing nutrient reductions secure for the long term?  And is nature genuinely better off than it would have been under the functioning system an EDP might replace?  

Natural England and Government must show that they will build on the existing market rather than undermine it. We need a locally designed approach that protects what works, addresses nutrient pollution directly and uses strategic investment to deliver more for nature, not less.  

Getting this right matters 

Done well, EDPs could unlock investment, accelerate nature recovery and provide a more strategic approach to environmental protection. Done badly, they could undermine successful local schemes and allow damage now in return for uncertain benefits later. 

The Solent should help lead this national debate. We pioneered practical nutrient mitigation and have evidence of what works. We now have a responsibility to help shape an EDP model that protects nature not only here, but everywhere it is introduced. 

Whatever comes next must deliver more for nature than what came before. If an EDP cannot demonstrate that it will outperform the functioning system it replaces, it should not proceed.