Planes, Trains and Automobiles

Cardiff Airport has been in the news again recently due to its continuing poor performance compared to its nearest rival Bristol, with one commentator saying that there should be no further investment in the airport because it is in the wrong place.

Cardiff Airport is in the Vale of Glamorgan to the west of Cardiff – it is 11 miles from Junction 33 of the M4, taking 27 minutes along mostly country and suburban roads. There is a nearby railway station at Rhoose, but with an hourly service to Cardiff Central taking 43 minutes it is not a viable transport connection.

But to be fair, Bristol Airport is also in the wrong place. Located in North Somerset to the south west of Bristol, it is also about 10 miles from the nearest motorway junction along country roads, and with no nearby railway station.

The two airports are in direct competition with each other but also lose potential customers to London Heathrow (business travellers), London Gatwick (holiday flights) and elsewhere.  Before the pandemic, Bristol had around 6 million passengers a year while Cardiff had around 2 million. Both airports were planning to expand further, but they would still be constrained by their poor road and rail connections.

A new airport built at a central location to replace the two existing airports would not only combine the passenger numbers of the existing airports, but should also be able to capitalise on improved transport links to attract passengers from further afield. An initial forecast of 10 million annual passengers is realistic.

Severnside Airport

Over the years there have been a number of proposals for a ‘Severnside’ airport to be built to the south-east of Newport, near Llanwern. Some of the earlier proposals would have involved concreting over a large section of the Gwent Levels – an historic area of reclaimed marshland that is now recognised as a protected area of Special Scientific Interest. This would never be acceptable today, and more recent proposals have involved building the airport on an ‘artificial island’ in the Severn Estuary. This gets around the NIMBY dilemma that everyone wants the convenience of living near an airport – but not so close that they are affected by its noise, traffic, pollution etc.

Building an artificial island sounds expensive and impractical and recent examples support this view:

  • Osaka Airport (Kansai) in Japan was built on an artificial island but this was in relatively deep water and required extensive and expensive reclamation works. It still suffers from ongoing settlement problems.
  • Proposals to build a new London airport in the Thames estuary at Maplin Sands and the unrealistic ‘Boris Island’ were poorly located requiring a huge investment in transport infrastructure.

But a Severnside Airport could be built close to existing transport infrastructure on an existing ‘island’ known as the ‘Welsh Grounds’, which is a rocky outcrop that is exposed at low tide. It would be a relatively simple engineering exercise to raise the height of the outcrop with backfill, using the nearby sand and gravel deposits.  The runway could then be aligned so that the flightpath for arriving and departing plans would be entirely contained within the Severn Estuary minimising noise disturbance.

Airport Layout

One of the problems Osaka Airport was that by placing the whole airport at sea, this significant road and railway bridges needed to be built with extensive terminal buildings situated offshore. This could be avoided with a split-site airport – all international airports are divided into ‘Landside’ facilities including arrivals and departures which are open to the general public, and ‘Airside’ facilities which are only open to passengers and relevant staff. I suggest building an airport on two separate sites:

An ‘Airport City’ would be built on part of site of the former Llanwern steelworks. This would include the main Terminal building, including all ‘landside’ departure and arrivals facilities, together with airport support facilities such as airfreight, logistics, car parking, hotels, etc.  This site is immediately adjacent to both the M4 Motorway and the South Wales Mainline railway.

Meanwhile, the runway(s), ‘Airside’ terminal and maintenance facilities would be built on an artificial island in the middle of the estuary. The runway(s) can be aligned such that the flightpath for arriving and departing plans would be entirely contained within the Severn Estuary and would allow it to operate on a 24-hour basis.

The ‘Landside’ and ‘Airside’ terminals would be linked by a ‘people-mover’ – a dedicated train that would run for around 5km and be restricted to ticketed passengers and staff only.  This arrangement is relatively common – for example in Kuala Lumpur International Airport (KLIA) in Malaysia, the Landside terminal at the outside edge of the airport is situated 1.5km from an Airside terminal which situated in the centre of the airport, with the two terminals connected by a ‘People Mover’ which takes 2.5 minutes to shuttle passengers between the two terminals.  This has the advantage of limiting the number of people travelling to the Island and reducing the size of the offshore facilities. There would need to be a limited road link to serve the airside facilities and support baggage handling, but it would not be open to the general public.

Transport Links

As mentioned earlier, the Llanwern site is situated just off the M4, with direct connection to the UK Motorway network.

This means that Passengers from Bristol would find it easier to get to the new Severnside airport than they can currently get to Bristol Airport. Welsh passengers living west of Cardiff would have to travel a little further, and I suggest they should leave the M4 at Tredegar Park and use an upgraded A48 & A4810 south of Newport to reach the Airport and so avoid the Brynglas Tunnels.

But the huge advantage of the Llanwern site is its location next to the South Wales Mainline railway. There are already plans to build a new station nearby at Llanwern as part of the South Wales Metro, and I propose to relocate this station around 1 km to the East and have all train services stopping there – including Intercity, regional and Metro services.

Cardiff, Newport and Bristol with their combined population of around 1.5 million are less than 30 minutes drive or rail/metro journey away, and this would be a reasonable ‘travel-to-work’ area for the airport.

A wider population of around 4.5 million across south Wales and western England is within 1 hours travel of the airport, while two hours travel would take in much of the English Midlands and Western London with a potential catchment of around 15 million people.

There is already a plan to open a Railway Station at Heathrow Termminal 5 with direct connection to Reading which would allow the introduction of an ‘Airport Express’ linking Severnside directly to Heathrow in around 75 minutes or less.

Tidal Energy

The site of the proposed airport is also a possible location for a Tidal Lagoon (see this earlier article), and the two developments could be easily integrated with the airport’s ‘island’ forming a large part of the lagoon’s containing barrier. While this should not be part of the Airport’s initial plan – to avoid extending the planning process – the airport plans should recognise this possible development and do nothing to jeopardise the potential future development.

Glan Hafren

While an expanded regional airport is a worthwhile objective, the big prize would be in developing the airport as an international hub – Emirates Airline has previously expressed an interest in developing a European hub to handle transatlantic flights and last year they expressed their dissatisfaction with Heathrow Airport limiting their flights.

There is already a massive shortage of runway capacity in South East England, and a new Severnside Airport would immediately offer a viable alternative, especially with a direct train connection to Heathrow.

So lets think big from Day one – A new Severnside airport could be

  • A regional airport for south Wales and western England
  • The eastern end of a transatlantic air-bridge to North America
  • The western end of a trunk route to Dubai
  • A Western European hub
  • Heathrow Terminal 6

Many people will now be thinking with alarm about how, done badly, a project like this could further dilute the Welsh character of this corner of Wales and integrate it increasingly tightly into the economy of Bristol and its region. But it needn’t be so. Ultimately this airport will be in Wales, and it’s up to us to make sure that anyone landing there knows it.

A good start is the name – we say it should be, not Severnside, but ‘Glan Hafren’. OK, the English-speaking world would need to learn that a single ‘f’ is pronounced ‘v’ in Welsh, but apart from that it presents no difficulty at all in pronunciation.

This project would not be cheap – costing maybe 1-2 billion pounds – but this does not have to be funded by the Welsh Government.  This is exactly the sort of infrastructure project that would be attractive to the Sovereign Wealth Funds of the Middle East especially if one or more of their airlines was involved – so let’s offer them the opportunity to build and own the project directly.

An Unwanted Stakeholder

There is a large elephant in the room – the Crown Estates. They currently ‘own’ the foreshore that the airport island would be built on, and they would undoubtedly expect a large payment for the privilege of hosting the airport.

But if the Crown Estates are devolved to Wales as they are in Scotland then this payment could be effectively waived with the Welsh Government retaining ownership of the Airport Island.


A new international airport in the Severn estuary would provide huge economic benefits to South East Wales – as well as the Bristol area. Equally importantly it should be possible to deliver with little direct public sector investment – The role of the Welsh Government would be primarily as an enabler not an investor. It should be possible to deliver the airport using existing devolved powers, but would need devolution of Crown Estates to make the scheme viable.


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