As London's airports feel the strain, 'Boris Island' is yet to take off

There is no shortage of proposals to ease the UK capital's crowded runways. But with the British government's stance ambiguous, scepticism is growing that an ambitious island airport will be built.

Rendering of the Thames Hub by Foster + Partners, Halcrow and Volterra. Image courtesy Foster + Partners

London needs more runways. Everybody says so. And they've been saying it for a long time.

"The United Kingdom has traditionally played a leading role in world aviation, but it is going to see that leading role badly eroded unless something is done about airport capacity in the south-east and that really means Heathrow," said Tony Tyler, the director general of the International Air Transport Association, at the group's annual meeting in Beijing last year.

"There is an urgent need for additional runways in the south-east of England, " the UK government also concluded, back in 2003.

"This national UK aviation strategy, or lack of it, has become the most talked-out topic in aviation economic history," according tothe Centre for Aviation [Capa]consultancy."The UK aviation scene is riddled with confusion, lethargy and incompetence."

Worldwide civil aviation has grown at an annual average of 5 per cent since the 1950s. Occasional recessions and wars have briefly delayed the growth over the years, but the trend is clear and continues today.

For London, one of the world's great hubs, all that growth means that Heathrow, its main airport, is already working at 99 per cent capacity.

"Passenger growth and future capacity of London's airports shows a shortfall in capacity of about 70 million passengers per annum by 2030, even when all other potential expansion is put in place," according to theestuary airport feasibility review, carried out for the mayor of London.

"This puts into perspective the debate on Heathrow and its uses as well as the need for further capacity. Even if these figures are optimistic they indicate an order of magnitude that demonstrates the need for another airport by or before 2030."

The issue is certainly gripping the current UK coalition government.

"At one stage there were no less than four inquiries in progress or planned to examine what the country should do about its lack of airport infrastructure," notes a cynical Capa. "Now there is only one that matters - the Davies Commission, which will not report until 2015. There is supposed to be 'cross-party support' for its findings, whatever they are, but that will be believed only when it is seen."

Out of this confusion, however, one man believes he has the solution. Boris Johnson, the mayor of London, wants a new airport in the Thames Estuary - dubbed "Boris Island" by the media.

The idea is not new.

In 1971, Edward Heath's Conservative government backed an idea to build an airport at Maplin Sands, reclaiming nearly 50 square kilometres of land, beginning with a single runway and one terminal but expanding to four runways by the 1980s, each of 4,250 metres, with 10 terminals arranged as a spine between them.

Access was to be by a non-stop rail service from King's Cross, taking just 40 minutes, and a motorway link from the planned M25 motorway. The airport was to handle 120 million passengers when completed in the 1990s. A £1 billion (Dh5.9bn) cost estimate was given for the entire project.

"If built, development at Heathrow would have stopped at three terminals and two runways and Gatwick would have remained with a single terminal and one runway, and west London and north Sussex would have been around 40 per cent quieter now," says David Hurst of the Royal Aeronautical Society. "However, in 2011, the six London- area airports handled over 135 million passengers; nearly 14 million more than the planned capacity of the completed Maplin."

The consortiums that have stepped forward to present their plans to realise Mr Johnson's dream are far more ambitious.

There is no shortage of institutions offering to put the money up, and four proposals are on the table. The latest is from the consulting engineers at Beckett Rankine and is for an offshore airport on reclaimed land on the Goodwin Sands, 3km off the coast of Kent and more than 100km from central London.

South Korea, Japan and Hong Kong already operate successful offshore airports, and Beckett Rankine believes it would be possible to create one for London for £39.2bn.

"We believe that an offshore hub airport is the only option that can realistically provide the four new runways that research reveals London needs," says Tim Beckett, the director of Beckett Rankine. "If the Davies Commission endorses the long-term requirement for a new four-runway hub airport for London, then locating it at Goodwin will have the least adverse social and environmental impact of any option."

Constructing a new airport at Goodwin Sands would have no effect on protected areas, shipping lanes or bird life as the region is not a recognised bird-breeding area. Beckett Rankine suggests connecting the airport to the high-speed rail line to London's St Pancras station.

"The mayor has been encouraging proposals for a new airport to the east of London and this proposal is welcome as a contribution to a critical national debate and as a demonstration that a new airport is feasible and deliverable, says his aviation adviser Daniel Moylan.

"The arguments for the construction of a new hub airport in the UK are overwhelming, and this proposal offers one option of how to build it.

"We now urgently need to recognise that a new hub airport is the answer to our aviation capacity problems and press ahead with considering the best way to deliver that airport."

The architect Lord Norman Foster has also unveiled his plan for what would be the biggest airport in the world. Jutting out from the Isle of Grain in Kent, on marshland adjoining the Thames Estuary, it would be just 30 minutes from central London by high-speed rail. Its four runways would handle 150 million passengers a year - more than twice as many as Heathrow - and operate 24 hours a day, all for a cost of £50bn.

The Boris Island concept need not be the multi-decade construction project that some believe. The Isle of Grain proposal by Lord Foster would take 14 years to complete, according to the law firm Bircham Dyson Bell, which was commissioned to investigate the planning implications. That is barely longer than proposals to extend Heathrow.

"This assumption that runway three [at Heathrow] is a quick win in terms of planning and policy process, let alone construction timescale, is incorrect," says Robbie Owen, a partner at the law firm.

Another idea is for a floating airport. The London Britannia Airport, designed by the architects Gensler, includes four floating runways tethered to the sea bed, with the option of further runways being floated in, allowing for future expansion. Passengers would check in and arrive at two terminals on land to the north and south of the estuary and a third central London terminal is proposed for Canary Wharf.

With its 5km long runways, open 24 hours a day, it would be capable of handling 150 million passengers a year from more than 400 gates. Access would be by jetfoil or high-speed rail from the mainland.

"It absolutely could be done. It's all fairly standard technology and marine engineering is what we're good at in Britain," saysthe project director, Ian Mulcahey.

"The idea of floating runways is fairly basic stuff - we're just proposing it on a scale, perhaps, that has never been done before. We're locked in a political debate about whether to build a little runway extension [at Heathrow] or whether we build a proper airport. This could be an airport for the next 100 years."

And still on the table after being rejected in 2003, is Marinair, an artificial island located within the shallow waters, 7km to the north-east of Whitstable in Kent, with four 4.5kmrunways and direct roadand high-speed rail links to London.

Douglas Oakervee, who wrote the estuary airport feasibility reviewreport at Mr Johnson's request, is of no doubt that picking one would be a good idea.

"Our report ... does not favour any specific location. It does, however, note that the area of the Thames Estuary does not present any insoluble issues," he says.

But the airlines want Heathrow expanded and are sceptical, and the UK government is terrified of having to underwrite the cost of a Boris Island on one hand and the electoral backlash of planting more runways in the overcrowded south-east on the other.

"This is a very difficult debate but the reality is that since the 1960s Britain has failed to keep pace with our international competitors in addressing long-term aviation capacity and connectivity needs," says the UK transport secretary Patrick McLoughlin.

"The government believes that maintaining the UK's status as a leading global aviation hub is fundamental to our long-term international competitiveness," he adds."But the government is also mindful of the need to take full account of the social, environmental and other impacts of any expansion in airport capacity."

Christoph Franz, the chief executive of Lufthansa, whose Frankfurt base is one of the chief rival hubs to Heathrow, is critical of UK government policy.

"It's a big mistake," he says.

"Aviation is not just an industry that provides jobs, it is a catalyst. You're in recession, you need growth, and you're keeping it away - it doesn't make any sense."

The Financial Times was more succinct.

"There are three options," it has said.

"An extra Heathrow runway, a new airport, or ceding London's [global financial] leadership. However it dresses it up, Britain's government has opted for the third."