In a statement issued this morning, the government announced its support for a new runway at Heathrow.
The Department for Transport's statement said that the scheme will now be taken forward in the form of a draft national policy statement (NPS) for consultation. The draft NPS will be published for consultation in the "new year", the statement said.
The DfT’s statement said that following the Airports Commission's recommendation in favour of a third runway at Heathrow, it had conducted further work on the environmental impact of the scheme.
"That work is now complete and confirms that a new runway at Heathrow is deliverable within air quality limits, if necessary mitigation measures are put in place, in line with the National air quality plan, published in December 2015," the statement said.
The statement also promised a "world class package of compensation and mitigation measures for local communities".
The package, which the government says is worth up to £2.6 billion, includes people with homes subject to compulsory purchase receiving 125 per cent of the full market value for their homes, plus stamp duty, legal fees and moving costs.
The DfT added that the mitigation package would include more than £700 million of noise insulation measures for homes and £40 million to insulate and ventilate schools and other community buildings.
Transport secretary Chris Grayling said: "This is an important issue for the whole country. That is why the government’s preferred scheme will be subject to full and fair public consultation.
"Of course it is also hugely important for those living near the airport. That is why we have made clear that expansion will only be allowed to proceed on the basis of a world class package of compensation and mitigation worth up to £2.6 billion, including community support, insulation, and respite from noise – balancing the benefits and the impacts of expansion."
It emerged last week that Prime Minister Theresa May has put in place a "special derogation" from the normal rules of collective responsibility to allow ministers some flexibility to set out their personal position on the matter.
The decision was seen as a sign that the Prime Minister was preparing to give the go-ahead to a third runway at Heathrow, which is opposed by foreign secretary Boris Johnson and education secretary Justine Greening.
At the end of last year, the government confirmed that the Planning Act 2008 regime for nationally significant infrastructure projects will be the route for delivering a planning decision on additional runway capacity in the South East.
Speaking earlier this year, former transport secretary Patrick McLoughlin said that, following a decision by the government on the preferred location of the new runway, there would be a draft NPS published for consultation and laid in Parliament.
The consultation could be for 16 weeks and would be followed by a "full-blown" select committee inquiry for 12 weeks, according to McLoughlin.
Duncan Field, head of planning at law firm Norton Rose Fulbright, said that, based on the example of the Nuclear NPS, it "could be another two years before the Airports NPS is both designated and free from legal challenge - possibly even longer".
He added: "Depending on whether Heathrow decides to begin the application process in parallel with the government progressing the NPS, it could then be another two or three years after designation of the NPS before development consent is finally obtained and a further year or more before all legal challenges are exhausted."
According to Field, while the NPS will clearly identify Heathrow as the preferred option for a new runway, it is very unlikely to exclude other sites completely. "This and the timescales involved give Gatwick a genuine window of opportunity, Field said.
"it is conceivable that Gatwick will be able to demonstrate that the benefits of its second runway outweigh any harmful impacts and either that it can meet the need for runway capacity in the timeframe identified by government or that it will not prejudice the delivery of a third runway at Heathrow and can cater for additional need over a slightly longer timeframe," he added.
Jonathan Manns, director of planning at property firm Colliers International, said: "The extension of Heathrow will undoubtedly precipitate a review of housing and employment forecasts in West London and the Thames Corridor. Spatial designations, such as the green belt and strategic gap which separates Hillingdon from Slough, will be permanently impacted by construction of a new runway and rail access."