SWOT for new Thames Airport

Advantages

Many advantages have been claimed for an airport in the Thames estuary, particularly as a replacement for Heathrow:^[5][8][11]

• Flights would no longer arrive or depart over densely populated areas of London.
• Noise and air pollution would be much less of a nuisance, because the new airport would be in an unpopulated area.
• As many runways and terminals as necessary could be constructed, without destroying existing settlements, whereas Heathrow is hemmed in by residents.
• Flights could arrive and depart at all hours.
• A high speed rail link to London with a journey time of around 20 minutes would encourage more passengers to reach the airport using public transport. Objectors point to the possibility that a high speed rail link to Heathrow could also be built. However, such a link would require expensive tunnelling under London, and was costed in July 2008 at £4.5bn.^[12]
• A high speed rail link to the nearby High Speed 1 would make London's airport a more suitable hub for north-western continental Europe: closer, and easier to reach.
• Under the Shivering Sands proposal, it would be possible to reach the airport from terminals in both Kent and Essex, diminishing the amount of new traffic and congestion imposed on either county.
• Regeneration of the deprived Thames Gateway.
• Release of 2,500 acres (10 km²) of prime land at Heathrow, close to the M4 and with excellent rail links, highly suitable for housing redevelopment.
• Traffic in west London would be greatly eased.

Disadvantages

A number of disadvantages to an airport in the Thames estuary have been pointed out:^[5][6]

• A floodplain or artificial offshore island is a vulnerable place for major infrastructure in a world where sea levels are rising.
• It would require major investment in local infrastructure (roads, railways, schools, hospitals) in order to service the tens of thousands of employees at a major airport.
• There would be considerable upheaval involved in moving London's main airport to a new location, though other major cities have successfully moved their main airport, including Paris (1974), Munich (1992), Denver (1995), Oslo (1998), Hong Kong (1998),Kuala Lumpur (1998), Athens (2001), Bangkok (2006).^[8]
• There would be significant job losses at Heathrow, and knock-on impacts to the economy of west London.
• The construction costs of the airport alone would be large, estimated at £11.5bn for Cliffe, and £3.5bn more for an offshore island scheme.
• There would be large costs for constructing road and rail access to the airport. These were estimated at £1.8bn for Cliffe, including two rail connections to High Speed 1, a road tunnel under the Thames to Benfleet, largely to access the south east Essex labour market, and other road and rail connections.
• Proposals rely on using capacity on High Speed 1, which may be scarce.
• Building an artificial offshore island is time-consuming, adding 3 to 5 years to the construction time.
• The risk of bird strike is higher for coastal sites, although less so for off-shore sites.
• The level of demand for an airport in the Thames estuary is uncertain, and may require government intervention to force airlines to use it.
• Building a major new airport to expand capacity may encourage more flights, and thereby increase emissions of CO2 and other greenhouse gases.
• The presence of the wreck of the SS Richard Montgomery, which has around 1,500 tons of explosives on board. A way to remove the wreck safely, present since 1944, has not yet been found.
• NATS are not in favour of the proposals. It would require a radical upgrade to the current flight patterns which are based on 1970s patterns and the proximity to Dutch and Belgian airspace would cause knock on effects in other countries.