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Is Boris Island in the Thames Estuary a fantasy island?

London mayor Boris Johnson is hoping a plan to build a new island airport in the Thames Estuary will head off a third runway at Heathrow. But as Alexandra Wynne reports, the London project may not be Europe’s first offshore airport, if the Dutch have their way.

Next month a major feasibility study into the construction of a new airport in the Thames Estuary is due to be completed. The study is being carried out by Douglas Oakervee, the engineer behind Hong Kong’s Chek Lap Kok airport, and currently Crossrail’s executive chairman.

The project has been nicknamed “Boris Island”, owing to the support of London mayor Boris Johnson, a vocal opponent of plans to expand Heathrow.

Click here for the London estury airport plan

Since coming into power last May, Johnson has spoken out against the proposed third runway at Heathrow, claiming the airport is “not fit for purpose”. He has said he is prepared to mount a legal challenge if the government is found to have bypassed procedures in approving the plans. Late last month, just as MPs prepared to debate the Heathrow proposal, Johnson embarked on a reconnaissance mission around the mouth of the Thames, hoping to flesh out his idea.

Early indications are that a four-runway airport could be built. Its £40bn price tag would include the cost of connecting the new hub to rail and road links into London. It is likely to include connections to High Speed 1 and Crossrail as well as work to widen and extend the M2 in Kent.

Preliminary ideas involve splitting the airport between a terminal in Essex on the north bank of the Thames estuary and four runways built on two islands at the mouth of the river. The islands would be connected to each other, as well as to Essex and Kent via tunnels beneath the riverbed.

The whole scheme is expected to take about eight years to build. No details have emerged on the exact site that Johnson and Oakervee have set their sights on. But following the scouting trip, Oakervee confirmed that “there is a remote site where an airport could be built with minimal disruption to people of Essex and Kent”. He added: “There are technical issues to be addressed but I see no overwhelming obstacle. We now need to work with other experts to address the challenges.”

Oakervee’s comments support the idea that Johnson’s scheme is perhaps a response to one of Johnson’s strongest criticisms of the Heathrow plans – that the additional noise disturbance would make living on the flight path unbearable. In contrast, the logic of the east of London option rests on the fact that flights would take off and land over water – avoiding the nearby towns of Southend-on-Sea in Essex and Sheerness in Kent.

The proposal is not entirely new – a version of the London airport in the south east was first conceived as far back as the early 1970s. Approval had been given for an airport at Maplin Sands, off the island of Foulness and close to Southend-on-Sea. However, strong environmental opposition and the economic impact of the oil crisis killed off the idea and the government opted instead to build Terminal 4 at Heathrow.

The notion of building airports on artificial islands is not uncharted territory either. As well as Chek Lap Kok, Japan’s Kansai airport springs to mind. Experience in driving through such projects will be invaluable if the Thames Estuary airport is to gain momentum. So having Oakervee on board to lead the feasibility study will be a huge help for Johnson’s campaign.

Whichever location is earmarked, Oakervee predicts the technical challenges will be less stretching than those he faced in Hong Kong, where the project involved flattening two islands. “I’m encouraged – from an engineering perspective it is quite clear that the mayor’s ambitions could be realised and that construction would be easier than that of other airports such as Chek Lap Kok and Kansai,” he says.

But as momentum behind the airport gathers, it is clear it will face competition from another plan now hatching across the sea in the Netherlands. There, consultant Royal Haskoning and marine contractor Van Oord have come up with a similar proposal which will add capacity to Schiphol airport near Amsterdam. The two firms worked on the mega-land reclamation project that is Dubai’s Palm Islands, and want to use this experience to build a massive offshore airport.

This will be 20km out to sea, built on artificial islands and including floating and rotating runways. The airport could be operational 24 hours a day seven days a week and would help the Netherlands gain prime position as the aviation gateway to Europe after 2025, when Schiphol airport will have reached maximum capacity.

Click here for the proposed North Sea airport extension

Despite Oakervee’s view that the new London airport might be easier than some to build, others’ experiences on similar projects might prove helpful in meeting the challenges. Already concerns have been voiced. Some have warned about the risk of bird strikes on planes.

Meanwhile, reclaiming land can be tricky. Kansai airport opened in 1998 and is often referred to as the sinking airport. Although Kansai’s terminals were fitted with jacks to counteract settlement, settlement took place at a faster than expected rate.

As the government pushes harder on the Heathrow third runway, all eyes – from local residents to MPs and engineers – will be on Oakervee’s report when it emerges, if as expected, in March.


Writing in his column for the Daily Telegraph last December
“We can all agree that it makes little sense to entrench a colossal planning error of the 1940s by expanding Heathrow in a way that will have all sorts of damaging impacts on the capital and the lives of its citizens”

In his transport policy document Way to Go! Planning for Better Transport, which was published in November 2008
“We all know that Heathrow is in the wrong place and no mayor could accept the greatly increased noise and pollution resulting from a third runway. That is why I have asked GLA [Greater London Authority] and TfL [Transport for London] officials to produce an initial report into an island airport in the Thames Estuary; and if they think it could work, then I will commission a full-blown feasibility study into an idea already gaining strong support in Parliament and among the public.”

In a statement on 15 January following the government’s announcement that it would give the go ahead for a third runway at Heathrow
“This is a truly devastating blow for millions of Londoners whose lives are now set to be blighted by massive increases in air pollution and noise. The government has singularly failed to deliver a convincing case for expansion throughout. I am deeply concerned that the proper processes of coming to this decision may not have been followed, and I will support a legal challenge should this prove to be the case.”

During a reconnaissance of possible sites for a new Thames Estuary airport on 23 January “Today’s trip has reaffirmed in my mind that a new airport in the Thames Estuary has got to be factored in as an option for London’s long-term aviation needs. I am reassured by a number of aspects of this visit and will now eagerly await Douglas Oakervee’s initial feasibility study.”

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