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Thames Estuary

Plane landing

We are vehemently opposed to the construction of an airport in the Thames Estuary and that includes any and all the latest proposals – and there are at least 6 of them now! – coming forward as part of the Government's review into the UK's aviation capacity.

This world-class coastal wetland has been threatened by a series of ill-thought out airport proposals over the past few decades. By campaigning alongside local communities and many others we have ensured none of them have come close to getting off the ground.

Since Mayor of London, Boris Johnson, catapulted the concept of an airport in the Thames Estuary back to prominence, all sorts of ideas have been put forward. These include one by Lord Foster on the Hoo Peninsula, a resurrection of the Cliffe airport idea, a floating airport and a new island in the estuary just off the Whitstable coast.

A Government Commission has been set up to examine aviation capacity and the need for expansion. The Commission will produce final recommendations in a report to be published in 2015, after the next election.

However, the Commission is due to produce an interim report at the end of 2013 highlighting locations they believe are suitable for a new hub airport. Despite the damage to wildlife and the risk of birdstrike, it is likely that this will include an option for an airport in the Thames Estuary.

The construction of a Thames Estuary airport is likely to result in an unprecedented level of damage and destruction internationally recognised and protected coastal wetlands in the UK. In addition, we have serious concerns about the wider impacts of aviation expansion on people and wildlife as a result of the increased carbon emissions.

We will actively campaign to ensure that any such plans are rejected and that aviation expansion only goes ahead when the risk to our environment are fully and properly taken into account.


The Thames Estuary is a large coastal wetland that is a vital migration hub for hundreds of thousands of wildfowl and wading birds. Some spend the winter in the Thames, feeding on its mud flats and salt-marshes, others are in transit between their Arctic breeding grounds and winter homes further south.

The global significance of the Thames for its birdlife is recognised by a series of Special Protection Areas that all but cover the entire estuary. There are also two Special Areas for Conservation.

Proposals to build airports in the Thames estuary are nothing new – dating back to shortly after the Second World War – their regular rejection on business, aviation, safety and environmental grounds is a signal from history that this is a bad location for aviation.

The Estuary's wildlife importance has more recently been recognised by the Government when it was awarded Nature Improvement Area (NIA) status. There are only 12 NIAs in the country and they have been set up to enhance some of out most important places for wildlife.

Proposals to build airports in the Thames estuary are nothing new – dating back to shortly after the Second World War. That all of them have been rejected on business, aviation, safety and environmental grounds is a signal from history that this is a bad location for an airport.

Time has moved on and our understanding of how climate change affects the environment has increased massively. So today, as well as the direct damage to wildlife, we can also add the threat of climate change to the dangers presented by airport expansion in Thames estuary (or indeed anywhere else).

We are in no doubt that the proponents of the latest airport proposals are serious, but to some extent that jumps the gun. The airport proposal was catapulted to prominence deliberately ahead of a crucial aviation review and the Commission that has subsequently been set up to look at the issue in detail. We welcomed the establishment of the Davies Commission at it should allow an objective review of the facts, away from the hype and simplistic claims of some supports of a Thames Estuary airport.

More generally, rhetoric used by the Chancellor of the Exchequer has revealed a worrying (and in our view deeply flawed) view that the environment can too easily be sacrificed for development at costs that can not be sustained by our natural environment.

It is this political and economic context that makes the Thames Estuary airport proposal even more significant. Were it to go ahead it would almost certainly be the largest single deliberate act of protected wildlife habitat destruction ever perpetrated in the UK and it would raise serious questions about the Government's commitment to being the greenest Government ever.

Airport expansion on this scale could also blow a massive hole in the UK's legally binding carbon emissions targets. Climate change is one of the greatest to threats facing wildlife and people in the long term. Failure to address it effectively will be catastrophic.



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Some of our most vulnerable wildlife and our most important habitats face potentially devastating impacts from proposals for new airports or runways in the UK.

Even areas like the Thames estuary are threatened. This wetland home for 300,000 migratory birds, where mudflats and marshes teem with life, has such high international importance that it has the greatest levels of protection possible.

The Government’s independent Commission on aviation expansion and airport capacity has been impartial and objective so far, but several of the 50 or so proposals they have received are very worrying, given the impact they would have on important habitats and our climate.

The Commission has called for comments on the proposals so we now have a brief window of opportunity to encourage them to take our environment, nature and climate into consideration as they narrow these proposals down to a short-list.

Help defend the future of vital sites for wildlife by emailing the Commission today.

See Downloads (right) for a printable poster.


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That so much of our natural coastal environment has survived in the Thames Estuary into the 21st century is something we should celebrate. At the RSPB, we are proud of the role we have played in protecting, nurturing and sharing the wild landscapes of the Thames in Kent, Essex and Greater London.

Proposals to construct an airport in the Thames go back to just after World War II when Cliffe was rejected as the site for a new airport in favour of a small village to the west of London called Heathrow. Indeed the challenge of plans to build on Maplin Sands off the Essex coast over 40 years ago was the stimulus to developing an objective approach to conservation planning. It led directly to the establishment of the Birds of Estuaries enquiry, a forerunner of the modern Wetland Bird survey that underpins so much of our knowledge about the importance of our coastal wetlands for bird conservation.

The Thames Estuary is one of the most important wetlands in Europe and is protected by an array of designations.  Perhaps the most significant of these are the Special Protection Areas, which are there to protect the internationally important flocks of migrating birds – over 300,000 of them spend each winter throughout the estuary before they head back to the arctic to nest. There are also Ramsar sites (a global marque applied to the planet's most important wetlands), Special Areas for Conservation, Sites of Special Scientific Interest, National and Local Nature Reserves. You can also find several RSPB nature reserves (covering a total of over 50 square kilometres) right across the Greater Thames. Although being an RSPB nature reserve doesn’t convey any legal protection on the site, it is an indication of how important we believe the area is for wildlife – and, of course, gives people great opportunities to see that wildlife for themselves. 

A similar proposal to construct a four-runway airport in the same area was rejected nearly a decade ago following our No Airport at Cliffe campaign. Since then various flights of fancy have emerged proposing estuary airports, but none of them have progressed into a real proposal. Now, with the review of airport capacity in full swing, there are no less the 6 separate proposals for airports, big airports, in the Thames Estuary.

Perhaps the most widely promoted  option (from Lord Foster) – four runways on the Isle of Grain with linking infrastructure – has been propelled into the eye of a media storm but still exists only as  architects drawings and plans.

We believe that the option of an estuary airport should be rejected outright. After several months of prevarication, the Government announced that they would set up an independent commission to assess airport capacity and the need for aviation expansion. The Davies Commission was set up in late 2012 and is currently taking evidence on a range of issues relating to aviation expansion. We have submitted evidence on a variety of topics and will continue to do so as appropriate. Those submissions include an independent report by CE Delft, which we commissioned WWF and HACAN (the group opposing Heathrow expansion), that questions the economic justification for aviation expansion. You can download those submissions by clicking on the links in Downloads on the right of the screen. 

The Commission will publish an interim report at the end of 2013 and their final recommendations will appear in 2015, after the next General Election. We believe that a Thames Estuary airport should not be included as a viable option in any new Government strategy and we will be working hard to ensure that this is the case.

We oppose this airport proposal because the massive environmental impact is unjustified. It would cause and unprecedented level of damage and destruction to internationally important and legally protected wildlife habitat, which we do not believe can be adequately compensated for.

We oppose the airport because to land planes in a foggy, bird-rich estuary makes it the most unsafe locations in the UK. Birdstrike would be up to 12 times more likely here unless draconian clearance of the flocks that make the Thames their home is undertaken, year after year.

We also oppose this airport proposal because it would be the world's largest airport and would lead to the generation of massive carbon emissions at a time when we urgently need to reduce emissions from all sectors in order to meet the UK's short and long term climate targets.

Finally, we oppose this airport proposal because of the so far un-quantified impacts on the important fish spawning and nursery grounds in the estuary and the subsequent effect on established fishing operations. Development of the scale proposed would alter tidal flows, changing erosion patterns with potential negative outcomes for the estuary's busy shipping lanes.

The myth that North Kent is an unoccupied wasteland awaiting development is not reality. There are strong local communities who have banded together in the past to oppose similar schemes that threatened their homes, ways of life and precious local environment. Their deep commitment to protect this historically and environmentally important landscape for future generations to enjoy is as strong as ever.


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Wreck of the Liberty ship SS Richard Montgomery off Sheerness – packed with explosives the wreck is still a major hazard in the area.


Cliffe rejected as an airport location in favour of Heathrow, flying boat operation suggested instead.


Flying boat plans dropped.


Cliffe rejected in favour of Gatwick.


Cliffe rejected in favour of Stansted, Foulness identified as a potential third London airport option.


Recommendation that Cliffe option be further considered at Stansted public inquiry.


Cliffe rejected as an airport option again.


Roskill Commission finally selects Foulness (Maplin Sands) as option for an airport. The risk to the nature conservation importance of the estuary was apparent but un-quantifiable – leading to the establishment of the Birds of Estuaries Inquiry (run by the BTO) the forerunner of the Wetland Bird Survey (WeBs) which continues to provide vital information to support wise decision-making to this day. Foulness kick-started the modern objective approach to site-safeguard.


Plans to build an airport on Maplin Sands off Foulness, Essex were scrapped.


Further promotion and consideration of the Maplin option (at a smaller scale) was rejected by the Government.


South East and East of England Regional Air Services consultation once again brought Cliffe into consideration prompting the RSPB to launch No Airport at Cliffe. A second proposal on the Hoo Peninsula (Thames Reach).


Aviation White Paper rules out the Estuary airport at Cliffe on the grounds of cost, environment damage and a greater risk of birdstrike. Thames Reach proposal also rejected.


London Mayor Boris Johnson begins serious promotion of an estuary airport as an alternative to a third runway at Heathrow – this continues a series of such proposals dating back to the 1980s.


Douglas Oakavee issues a preliminary assessment of 'Boris Island' and recommends further studies.


The 'miracle on the Hudson' plane crash caused by bird strike raised the issue of safety in connection with estuary airports in public consciousness.

July 2012

The government announces delay in consultation on the economic arguments for a hub airport until later this year

November 2012

Davies Commission established to examine options for airport expansion

March 2013

Government publishes Aviation Policy Framework

December 2013

Davies Commission to publish interim report recommending options for a new airport


Davies Commission to publish final recommendations in the summer, after any general election.


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