A guest post from Daniel Moylan, the Mayor of London’s Chief Aviation Adviser

London’s prosperity depends on its remaining a truly global city; it is the powerhouse of the British economy in part because it is our gateway to the world. And since London is the capital of an island-nation, it is hardly surprising that much of that connectivity is by air: 85% of people arriving in and leaving the UK do so on a plane.

That is why London’s airports are so important. For historical reasons, however, instead of having a single major airport to serve the capital, there is one dominant but constrained airport at Heathrow supplemented by a clutch of smaller airports, such as Gatwick and Stansted, each of which has been developed because Heathrow is so constrained, but neither of which has turned out to be the right answer to the question, How should London’s growing need for aviation connectivity be addressed?

Heathrow argues that the best connectivity – and the widest choice of destinations for passengers – comes from having a large “hub” airport, similar to those in Amsterdam, Paris, Frankfurt, Atlanta and Dubai. And Heathrow is right about that. The handful of other cities that have multiple medium-sized airports (such as Tokyo and Moscow) have struggled to generate hub business – in Tokyo’s case it has been lost to the hub airport in Seoul – and so struggle to give their own residents and businesses the choice of destinations and frequencies they need to prosper.

So Heathrow has a good point. But the problem the airport management refuses to acknowledge is that Heathrow has already outgrown its premises. Its airfield is half the size of Paris Charles De Gaulle and, while it might be physically possible to tack a third runway onto the airport by moving and tunnelling the M25, real long term growth can only come from relocating to a site where these physical constraints cease to be a challenge.

And even more markedly, Heathrow fails to recognise that expansion of the current airport is environmentally and politically undeliverable. Already Heathrow is the most noise-polluting airport in Europe, blighting the lives of over 700,000 people in their homes. Heathrow management asks us to accept that with a third runway (one of them operating in mixed mode) and an assumed 50% increase in flights, there will be less noise from the airport than now. Of course nobody actually believes that.

So we face the conundrum that we need Heathrow to grow – it is running at 98.5% full at the moment – but we can’t let Heathrow grow at Heathrow. It doesn’t require a genius to see that the answer is for Heathrow to relocate. But it does require some courage to fight for Londoners in that cause and that is what Boris Johnson has been doing for the whole of his time as Mayor. Other cities have done exactly this: Hong Kong moved its airport to a barely inhabited island in the middle of the sea – and released huge economic benefits in doing so. Denver in Colorado and Munich in Germany have done the same.

In Britain there is a perpetual chorus of doubt and nay-saying on the theme that foreigners can do those things, but we cannot – even though a great number of engineers and architects working on new airports globally are in fact British. We have the expertise; all we need is a bit of British grit and we can give our city and our country the airport it needs for the coming century.