Tim Leunig: The best solution for business and for Londoners is a quieter Heathrow with more western runways

Tim Leunig is the Chief Economist of CentreForum. Follow Tim on Twitter.

All parties get themselves into tangles at one time or another, and the Conservative party has got itself in a tangle over aviation. Most Conservatives instinctively favour airport expansion. The market supports it, business supports it, and most people expect the Conservatives to support it at the next election.

But Zac, Justine and Boris have a point. Heathrow has a noise problem. That is why Boris – helped along by Foster + Partners – has come up with a new plan for an airport in Cliffe. It would be quieter, no doubt about that.

But it is also in the wrong place for business. A quarter of business travellers using Heathrow get to the airport within 30 minutes. That would be impossible at Fosters’ proposed airport, unless you live at St Pancras station, or the Medway towns. An inaccessible airport just doesn’t work – as Montreal Mirabel so clearly demonstrates. That is why Willie Walsh and other airlines prefer to stay at Heathrow. It is an airport that works for business.

So what we need is a bigger, quieter Heathrow. Bigger means four runways. Every major city has a four runway airport: Paris, New York, Madrid. Boris is right: that is what London needs.

Thankfully it proves to be easier to design a quieter, four runway airport than perhaps we first thought. The simplest way to reduce noise is to land planes further to the west. Put simply, more people live east of Heathrow than west of Heathrow. That is why HACAN, the Heathrow Association for the Control of Aircraft Noise, have campaigned for planes to land a little further west for years. A larger, quieter Heathrow is based around replacing the current two runways with four new ones, located to the west of the current runways, over the M25 and Wraysbury reservoir.

The second simple step to reduce noise is to keep the runways relatively close together. This means that fewer people live under the flightpath. Together, these two factors reduce the number of people affected by daytime noise by a quarter, even though the number of planes would rise by three quarters. Bigger and quieter are not incompatible.

But we can go further. Anyone who has ever been woken by the 0450 arrival from Hong Kong will tell you that day time noise is not the big issue. It is night flights, and particularly the early arrivals from the Far East. There are only a handful of such flights, but even a handful is a handful too many for people living in the flight path. With more slots available it is feasible to end night flights altogether. No ifs, no buts.

We can go further in reducing day noise as well. Anyone who has ever sat under the flight path knows that some planes are noisier than others. We already restrict the noisiest planes – but only at night. We should go further, and restrict them during the day as well. With enough notice the airlines can adjust their fleets so that only quiet planes are used on Heathrow services, further reducing noise nuisance.

We can also learn from London City, where planes land more steeply, reducing the noise nuisance in the locality. It is not reasonable to expect that we can land very large planes at a steep angle – the laws of physics are immutable – but we could and should be aiming to land smaller planes more steeply by the time any new airport opens.

At this stage it is not possible to cost the proposal accurately. But much of the existing infrastructure is already in place. Terminals 1-3 and 5 would remain in place, along with their associated piers and jetways. The existing airport would be reused as taxi way and aircraft storage. The maintenance and engineering depots would continue, as would fuel supply, air traffic control and so on. The Heathrow Express and Piccadilly Line need only minor changes, and a direct line to Waterloo, Reading and Woking can be provided at low cost. For all of these reasons it is hard to see the cost exceeding half that of any other four runway proposal. One area where no corners should be cut is compensation for those who have to move. That is true for this and every other airport expansion proposal.

Taken together this package offers a new deal for passengers, for airlines, and for people in and around London. Conservatives should unite around it. Boris, Justine and Zac are right: Heathrow is too noisy, and noise matters. But the bulk of the Conservative party is also right that we should listen to business and passengers, and see where they want to fly from. Since we can reconcile both aims – and at a price that makes sense – well, what’s not to like?