Cabinet discussed the issue of airport capacity in South East England on 18 October 2016. A leaked letter confirmed that no decision was made, but it revealed what will happen next.

There will be a meeting of the Cabinet Economic and Industrial Strategy (Airports) sub-Committee tomorrow Tuesday 25 October 2016. The PM's letter reveals that the meeting "will decide upon a preferred scheme for the expansion from the three options recommended by the independent Airports Commission last year [2015]".

Over the weekend, Chris Grayling Secretary of State for Transport has said that the Government had still not decided which option to choose and would make the final decision on the day. He is expected to announce the choice to the House of Commons as soon as it has been made.

Last year, the then Secretary of State for Transport (Patrick McLoughlin) confirmed that the mechanism for delivering planning consents for major airport expansion will be an 'Airports National Policy Statement' (NPS). Major airport expansion, according to the Planning Act 2008, is an expansion that will result in an increase in air passenger transport services for at least an extra 10 million passengers per year. A project that meets this threshold, and all three options do, is then consented as a Nationally Significant Infrastructure Project (NSIP). An Airports NPS will be the specific policy basis for determining an NSIP application.

The leaked letter confirms that the Government intends to publish a draft NPS. The timescale given in the letter reveals that the Government aims to designate the NPS in winter 2017/18. Previous NPSs for other infrastructure consented as NSIPs, have taken about a year to get from publication in draft through consultation and Parliamentary approval to designation. We can therefore expect that a draft Airports NPS will be published soon, perhaps tomorrow.

NPSs have a special purpose in the Planning Act 2008 consenting regime. It is to set out the overarching national policies, as well as to determine need for the infrastructure. This is to ensure that the policies and need may not be reopened for debate at public examination on individual NSIP applications.

Because the NPS settles important questions of need and policy, the Planning Act 2008 requires increased democratic accountability and a formal process of designation. Hence also the need for statutory consultation on and Parliamentary approval of the draft NPS.

If the draft Airports NPS identifies one or more locations as potentially suitable for development, as is likely, then public consultation must also be carried out at those locations.

When consultation on the NPS is complete, the Department for Transport will prepare the final draft of the NPS taking into account the responses received. The last stage of the process then follows and the final proposed NPS must be laid before Parliament for scrutiny. Only after Parliamentary scrutiny can it be formally designated and come into full effect.

When the final proposed NPS is laid before Parliament for scrutiny, it can be either formally approved by resolution of the House of Commons within 21 sitting days, or a period of 21 sitting days expires without the House of Commons resolving against it. Parliament could vote not to approve the NPS, but this is perhaps the less likely outcome.

The consultation on the draft NPS will be the only formal opportunity for MPs to have a say on something which would directly affect any proposed airport expansion (wherever it may be). The Transport Select Committee may also want to scrutinise the draft NPS, as was the case with the previous NPSs on ports and national transport networks. But there would be no Parliamentary Bill specifically on Heathrow (or elsewhere), no opportunity for MPs to vote a proposal through or vote it down, or to amend the proposal in Parliament.

The major advantage of having a designated NPS is that it speeds up the process for receiving a Development Consent Order (DCO) for an NSIP application. After completion of a public examination that follows a strict timetable, the DCO grants the planning consents and compulsory acquisition rights to implement a project. An examination based on a designated NPS also reduces the risk of legal challenge.

The Waste Water NPS, which is already in place, contains the generic policy on the factors to be taken into account for a major waste water project. Then in the annex it refers to two specific projects, Deephams Sewerage works and the Thames Tideway Tunnel, both of which could be progressed as NSIPs.

The draft Airports NPS will provide the factors to be taken into account for any major UK airport expansion. It could also refer to one or two or all of the options identified by the Airport Commission, in the same way as for example the Waste Water NPS.

The three options are: a third new runway at Heathrow (estimated at £18.6 billion, plus an additional £5 billion for road and rail schemes), a new second runway at Gatwick (estimated at £9.3 billion), and extending the existing northern runway at Heathrow (estimated at £13.5 billion).

Can a promoter prepare an application for a DCO if there is no designated NPS?

If there is no designated NPS this does not prevent a DCO from being prepared. However, the absence of a designated NPS will make it more complicated to bring forward an application and it is likely to increase the time it takes to do so. Particularly, because until up to date government policy on aviation is set out in a designated NPS, the Aviation Policy Framework (March 2013) will remain government policy. This policy is generally considered to be out of date, not only on matters of expansion in South East England but also on expansion elsewhere in the UK and at regional airports.

Can the Secretary of State take a decision on a DCO application, if there is no designated NPS?

If there is no designated NPS this does not, technically, prevent the Secretary of State from taking a decision on an application. The Planning Act 2008 contains powers for the Secretary of State to take a decision in the absence of the NPS. There are also powers for him/her to delay the decision.

Absence of a designated NPS is more likely to lead to a delay in any decision on an application. Much would depend on whether the Secretary of State at the time will be inclined to wait for the NPS to be designated or not.

Once the various stages of consultation, consideration and planning are taken into account it could be 2020 before a Minister is faced with giving a scheme final approval.

A DCO not only gives planning consent but also all other consents and orders including the compulsory acquisition rights for the project to proceed. Depending on specific surface access requirements, Transport and Works Orders may also be needed for delivery of a project but this shouldn't lead to any further delay.

The procedure for a DCO is the same if the Government decides to proceed with both Gatwick and Heathrow. Only, two applications would need to be made under the Planning Act 2008 regime; one for Heathrow and the other for Gatwick.

Gatwick, it seems, may attract less hostility and with probably fewer properties to compulsorily acquire, may be consented in a shorter timeframe.