Guest Blog from Prof. David Hill CBE

Photo: The Wash, lying to the West of freshwater marshes and coastal scrub at Wild Ken Hill


In this guest blog we hear from Professor David Hill CBE. David has decades of experience assessing development projects, from small housing schemes through to major ports, airports, reservoirs, infrastructure, recreation and renewable energy projects. Some years ago, David reviewed the efficacy of the proposed Severn Tidal Barrage on behalf of the then Sustainable Development Commission, and has advised on various port schemes around the coast.

At Wild Ken Hill, we are greatly looking forward to hearing David’s perspectives on the proposed Wash barrage. So, over to you David!


I have only recently been made aware of the very outline proposals for a barrage across the Wash and I immediately looked for a date of 1st April on the ‘announcement’. Having said that, vanity projects costing billions with no quantifiable benefit to people but hugely significant impacts to nature have been permitted before, so I felt that an initial analysis from my own experience might be of interest.

I founded one of the first environmental consultancies in the UK and then, in 2006, founded the Environment Bank, largely because of my frustration at promises made by developers that never materialise, not least because the developer is forced by the planning system to incorporate ‘biodiversity’ within a development, a liability they are seldom able to deliver upon.

Given the difficulties of enforcement by local planning authorities, in aggregate development continues to have a net negative impact on this country’s biodiversity. This is why I set up the Environment Bank: to provide a better way for developers to deliver biodiversity through the concept I devised for the UK of biodiversity net gain (BNG), which was mandated into law through the Environment Act in 2021.

Over the years I’ve represented many developers at public inquiries across many projects. We need sustainable development – for growth, for jobs, to improve people’s lives, to provide homes. But it is absolutely essential that those developments understand the impacts on the environment, with those for which impacts would be too great being refused permission. Growth at any cost leads to impoverished communities and devastated environments.

Key aspects of the planning system

Since biodiversity loss is recognised as an existential threat to humanity – equivalent in scale to that of climate change – it is ever more important that we properly assess development projects ensuring that ‘benefits’ are not overplayed and impacts are not underplayed. My experience is that in most cases this is exactly what happens.

That isn’t necessarily the fault of the developer or their planning advisers, but of the system; stretched planning authorities find it difficult to apply the same level of resource to evaluating a development application compared to a developer promoting that development.

There are many places across the UK where the quality of biodiversity is so high that any development would create unacceptable impacts. Ecologists apply what is called the mitigation hierarchy – avoid, reduce, mitigate and compensate to assess development projects; sites of highly significant importance must be avoided. For sites of European importance, the European Union created the Birds and Habitats Directives, transposed into UK domestic legislation via the Habitats Regulations.

The Habitats Regulations provide stringent sequential tests to a development that is likely to have a significant effect (termed LSE) on the features for which the site is designated. For sites that do not have priority species or habitats the test enables effective mitigation to be proposed and a method for compensation (usually creating vast areas of new habitat) where there are demonstrable socio-economic benefits that would accrue from the development which has an overriding influence on the biodiversity features. However, the tests set a high bar and many a development has been found wanting where the benefits have been overplayed. The developer rightly has to take all the risk, or at least his or her investors do.

How the Wash barrier would impact biodiversity

So, what about this proposal? The Wash and the coastal and marshland environments that abut it enjoy the highest levels of protection of anywhere in the world – Special Protection Area, Special Area of Conservation, Ramsar site, all underpinned by the Site of Special Scientific Interest series.

As has been referred to many times, the Wash is home to one of the largest concentrations of waterfowl – wildfowl and waders – of anywhere in the world. Its attractiveness to these vast numbers of migratory birds is because of its sedimentology, hydrographic influences, tidal range and coastal productivity, with many different substrates and sub-ecosystems providing a huge range of habitat opportunities for algae, macrophytic vegetation, benthic invertebrates, crustaceans and fish that in turn are prey for birds and mammals.

Many of these birds migrate to our shores from their artic tundra breeding grounds – Russian steppes, Greenland, Iceland and areas of northern Europe. The Sanderling, a diminutive wader makes a round trip of 26,000 miles every year to glean the resources of the Wash.

The Wash also provides home for a number of other species of conservation significance such as Harbour Seal, and breeding seabird colonies notably spectacular Little, Common and Sandwich Terns as well as breeding waders such as Redshank, Oystercatcher and Ringed Plover. The Wash provides a spectrum of foods on a phenomenal spatial scale.

Any disruption to these ecosystems would impact on the food supply in a catastrophic way. Altering the natural tidal cycle could collapse the food systems for waterfowl and have a catastrophic impact on fish breeding and fish populations generally. Crustacean numbers would collapse. Breeding terns would almost certainly abandon their historical breeding locations because of a lack of food to feed their chicks.

Feasibility of a potential Wash barrier

 So now to the challenge. The amount of survey and assessment work needed to even get such a project to the next stage would be eye-watering. For example, the developer would need to assemble a team comprising: planning consultants, marine and terrestrial archaeologists, ecologists, hydrologists, oceanographers, marine pollution specialists, civil engineers, construction engineers, bathymetric and sediment modelers, landscape/seascape design architects, traffic and highways analysts, financial viability analysts, noise consultants including underwater noise specialists, community engagement, PR and marketing consultants, and quantity surveyors.

The costs of assembling and deploying this team, for any interested investors, would almost certainly be close to £100m (compared to the £5m estimated by the developer). The timeframe to obtain enough information for an application would probably be in the order of 10 years. It took one well known water company 14 years to eventually get permission for the raising of an existing reservoir in the south of England!

Benefits do not stack up

Then there is the ‘why?’. Tidal barrage technology is a poor means of generating electricity compared to that from wind power – take a look at the plans for offshore wind around the UK and the predicted contributions to our energy supply – and solar. This is where renewable generation is focussed. The costs of these latter two are now comparable or even less than electricity generated from fossil fuels. The case for need and hence its viability would be incredibly difficult to make for this proposed barrage, even if there wasn’t the level of environmental destruction that it would cause.

The huge, land-locked lake created by a barrage would undoubtedly provide habitat for water skiers and the like, but the natural beauty of the whole of the north Norfolk and Lincolnshire coast would be lost. This beauty is the very reason so many discerning folk visit Norfolk and its surrounds – it offers something that just doesn’t exist anywhere else. The natural capital value of the Wash, its birdlife, scenic beauty, fish stocks, and feeling of wilderness that everyone can enjoy, is far greater than any value that could be derived from inefficient energy production and some kiss-me-quick water skiing. The economic net impact to the region would be massively negative.

Not costed properly

And if the Severn barrage was predicted to cost £34bn back in 2010, a barrage on the Wash would be multiples of this. Then when we factor in the HS2 effect (HS2 was predicted to cost less than £40bn but an independent review by Lord Berkley recently put the price tag at c.£115bn and rising), then any investor would surely find the aggregate risks enormous and unviable. The developer for this Wash barrage has estimated a cost of £2bn.

I haven’t even mentioned the proposed ‘port’. The economics of sea freight are fascinating. It is highly likely that both Felixstowe and London Gateway would throw fortunes at any public inquiry, to demonstrate the disbenefits of another port at this location because it would represent a threat to their businesses, perhaps already being impacted by Brexit.


This has been a very cursory look at how a proposal for a barrage on the Wash might play out. Massive costs, massive damage, massive risks. In my view this is unreservedly a development too far.

Professor David Hill CBE DPhil(Oxon) CEnv FCIEEM

March 2023