Why the Airports Commission ruled out almost everything

A Thames Estuary airport remains on the cards despite having many of the same problems as other proposals that have already been dismissed.

Almost all the options for increasing UK airport capacity with the exception of expanding Heathrow and Gatwick have now been ruled out.

Proposals to expand Luton, Stansted or Birmingham, build new airports at various locations around London, or create an orbital railway or maglev to turn the existing airports into a cross-city hub have all been deemed non-starters by the government’s Airports Commission, which released its interim report yesterday.

Sadly, but probably with good reason, so has the somewhat outlandish idea of creating an electromagnetic catapult system to speed up takeoff.

The only other option still under consideration – although not shortlisted along with new or extended runways at Heathrow or Gatwick – is for a new hub airport in the Thames Estuary, specifically on the Isle of Grain, which has been deemed the only suitable site for such a project.

There’s already been much speculation over the politics surrounding the report, with some suggesting the Estuary option has only been left open at the insistence of David Cameron and Boris Johnson – a major proponent of the scheme – in order to keep it on the table until after the election when the final recommendation will be made.

However, an Estuary Airport could still be ruled out as early as next year once the Commission has undertaken a more detailed analysis of one of the Isle of Grain option.

The Commission performed a ‘sifting’ operation on the 52 ideas it received, ruling out the most obviously flawed ones first before gradually narrowing the options down to a final four. The report provides short summaries of each of the rejection reasons.

Dispersed hub option

The idea to use Heathrow, Gatwick and Stansted together as a London hub spread over three locations was quickly dismissed as creating market distortions and operational inefficiencies.

Improve ground transport

The possibility of creating a London hub-and-spoke or orbital railway or maglev system to link all the capital’s five airports was also ruled out due to the difficulty of achieving acceptable transfer times and the plan’s inability to create the capacity needed ­­– and at high cost.

A national high-speed rail network to replace the need for domestic flights into London was also seen as costly and would only increase capacity by an equivalent of seven per cent of Heathrow’s current traffic.

London airports

Proposals to expand Luton or Stansted to multi-runway hubs were seen as flawed because expanding one would lead to the closure of the other and of Heathrow, which would either not increase capacity by sufficient amounts or be hugely costly and have a major impact on West London. Expanding Stansted would also have high costs in itself and require improved surface transport.

Regional airports

Several proposals were put forward for expanding other airports and all of them were ruled out. Birmingham was seen as too far away and expansion would rely on short journey times from London using HS2, which would actually make London airports more attractive to Birmingham’s current customers. Similarly, expanding Cardiff would need an extra HS2 link (costly) and wouldn’t deliver significant extra capacity.

New airports

Almost all proposals for new airports were ruled out for a handful of reasons: Maidenhead – too many houses to demolish and flood plain risk; Oxford – less noise disturbance and demolition but increased flood plain risk, too far from London and agricultural land too valuble; Milton Keynes – cheap and with good transport links but would shut Heathrow and Luton and so wouldn’t increase capacity; Foulness (Essex) – ongoing defence requirements; Twyford (Oxfordshire) –too far away without an extra HS2 station.

Severn Estuary

Bold proposals for an artificial island airport in the Severn wouldn’t add capacity where it was needed and wouldn’t add to national capacity as Cardiff and Bristol airports would need to close.

Thames Estuary

Numerous plans for an airport along or in the Thames Estuary were examined and almost all were rejected. Firstly, any locations in the outer estuary were seen as too far away.

A revival of 1970s plans to create an artificial island on Maplin Sands was not possible under current regulations and the site was seen as too close to a current munitions testing area.

Several ideas for an airport on the Isle of Grain were merged into a general proposal and assessed to have many of the negative points of other schemes: high cost, requiring extra surface transport, the necessary closure of Heathrow and environmental concerns.

But the Isle of Grain was seen as potentially having more benefit than any of the other ideas, and so the Commission has decided to take more time to weigh up whether this benefit outweighs the costs and risk.

Electromagnetic catapult

Finally, it was always going to be a long shot and the Commission found the idea of assisted takeoff too risky, slow and costly.