IoS exclusive: Secret plan for four-runway airport west of Heathrow

Ambitious plans for a four-runway airport near Heathrow are to be submitted to the Government as a solution to the aviation crisis that has divided the coalition, The Independent on Sunday can reveal.

A world-leading infrastructure firm is assessing sites to the west and north-west of London which could rival, or even replace, Heathrow to challenge other European hubs in providing air links with the Far East. Sites in Oxfordshire and Berkshire could potentially be in the frame for the airport, estimated to cost £40bn to £60bn.

Justine Greening, the Secretary of State for Transport, is to launch a call for evidence as early as this week on how to increase airport capacity, after winning a major political battle to rule out a third runway at Heathrow. All other options are on the table, and a brand new "London West" airport with road and rail links to the capital would be seen as a "wild card" capable of challenging the Thames Estuary airport idea backed by Boris Johnson, the London Mayor, and the architect Lord Foster.

Documents seen by The IoS confirm that specialist engineers who have worked on major aviation projects in North and Latin America have been asked to evaluate flat tracts of land that the consortium thinks might be suitable for such a huge project. The documents state: "Debate must be refocused to get political and business consensus on the criteria to be met by a future hub. As evidenced by HS2 [High Speed Rail], Crossrail, and the London 2012 Olympics, the development and delivery of any scheme must have cross-party backing and must be supported by business and the workforce."

The major feasibility study has been commissioned by a consortium of British businesses, which is expected to reveal itself within weeks and is understood to have started talks with Chinese sovereign wealth funds over funding the airport. Discussions with junior Department for Transport officials are also believed to have taken place over the summer, although sources indicated that Ms Greening was not aware of the details of the plan.

The IoS can reveal that the criteria in a confidential briefing document drawn up by the consortium to identify potential sites states:

* Environmental and noise requirements: any new site will need to have a 16km long x 3.5km wide glide path either side of the airport, without overflying large built-up areas

* A flat site to allow for runway layout oriented around west to east, or south-west to north-east direction, with terminals and associated infrastructure

* Be readily accessible by surface transport corridors... road and rail

* Be located no more than 30 minutes' journey time from London.

The transport links and journey times into the capital mean that the project's location is almost certain to be on the Great Western Main Line, which runs out of London through Maidenhead and is being revamped, or High Speed Two, the proposed 250mph rail link between Birmingham and London. The speed of the line brings locations further outside the M25 into play, including areas to the north-west of Heathrow.

The Conservatives opposed a third runway at the 2010 election, but in March it emerged George Osborne was keen to reconsider, under pressure from business groups who fear Britain is losing out to other European airports. But last week Tim Yeo, a Tory MP and former environment minister, challenged David Cameron to show if he was a "man or a mouse" by backing Heathrow expansion. And last month Mr Johnson told the PM to stop "pussyfooting around" on airport expansion and warned against kicking the issue into the long grass until after the 2015 election.

However, later this month the Liberal Democrats will restate their opposition to airport expansion. A motion at the party's annual conference in Brighton will "firmly" reject the Thames estuary airport, rule out new runways at Heathrow, Gatwick and Stansted, and propose better use of existing capacity.

It also demands an "independent, evidence-based study to find a location for a hub airport or a suitable airport to expand into a hub for the long-term" which could clear the way for the consortium's proposal.

Supporters of this airport believe Ms Greening could be open to the project, after opposing Heathrow expansion because of the impact on her Putney constituency.

The consortium wants the new airport to have four runways to compete with other major, growing airports such as Schiphol, Amsterdam, which has six, and Frankfurt and Paris Charles de Gaulle, which have four.

It is unclear if Heathrow would survive should the plans be accepted, though it is thought the two could complement each other in the first years of the new airport's operations.

An industry source said: "What this idea does is put people's pipedreams, like 'Boris Island', to one side and shifts the political debate away from Heathrow, to work on something that is based on properly grounded infrastructure requirements."

Pressed by The IoS as to why the consortium will not yet reveal itself, the source added: "These are very serious people. They want all their ideas aligned before coming forward publicly – this is going to be pretty impressive stuff."

Q&A: What can be done about the future of Britain's air transport?

Do we need a new airport?

We need more airport capacity, according to the Department for Transport. Without new runways London's three runways will be at capacity by 2030, and by 2050 annual passenger numbers will be 50 million lower than if there were no constraints.

Is Heathrow the problem?

Unlike most other airports in Britain, Heathrow is almost at capacity already, with 70 million passengers arriving and departing in 2011. Every day 190,100 pass through on 1,250 flights, drinking 26,000 cups of tea.

Why not expand existing airports?

Heathrow is Britain's only "hub" airport, where passengers arrive on a short-haul flight and then leave on a long-haul flight. Other airports such as Gatwick and Stansted are "point-to-point" airports, which fly direct to destinations where there is demand. Trying to link, say, Gatwick and Heathrow would make transfer times too long, it is argued. Residents living near existing airports are also likely to oppose more flights.

Why will no one make a decision?

There is no easy option. People like going on holiday and flying around the world on business, but they don't like being woken up by planes rumbling over at all hours. And when people come to vote, they'll think of their good night's sleep, not the good of the economy.

Where do the parties stand?

Labour backed a third short runway at Heathrow in 2003, but under Ed Miliband argues it is "now off the agenda because of the local environmental impact". David Cameron announced his opposition to a third runway in 2008, but senior Tories including George Osborne are agitating for a U-turn. The Lib Dems oppose any expansion of existing airports, but want a study for a new airport.

Is it about being green?

Yes and no. Politics play a big part too. Cameron's move to block the third runway was seen as the first major indication of his new environmental credentials, after his infamous huskie-hugging trip to the Arctic. But the real impetus was closer to home – there are votes to be won and lost among those living under the flight path. Some environmentalists, including Tim Yeo, chairman of the Energy and Climate Change Select Committee, argue that new Europe-wide caps on carbon emissions mean that new capacity can be supported, forcing additional reductions in C02 elsewhere.

Are we losing out to other countries?

According to most business groups, yes. With economic growth likely to come from China and South America, offering regular flights to these new markets will be crucial for long-term prosperity. Frankfurt has four runways and flies to 277 destinations. Amsterdam Schiphol connects to 247 destinations using six runways and Paris Charles de Gaulle has four runways serving 236 different places. By comparison, Heathrow's two runways serve just 162 destinations.

What about Boris Island?

In addition to the new west of London plan, revealed by The IoS today, there are other ambitious ideas on the table. Boris Johnson's scheme for an airport in the Thames estuary is just one. The architect Lord Foster has plans for another on the Hoo peninsula. None of them has yet found favour with ministers.

When will extra flights take off?

If a third runway were given the go-ahead, it could take a decade to build. A whole new airport could take longer, although Johnson claims his Thames estuary airport could be built in six years. Either way, no option will help the economy to take off soon.

Matt Chorley and Megan Archer