The public is being invited to comment again on the proposed third runway at Heathrow Airport after the Government published new evidence relating to the expansion.
The reports, published by the Department for Transport (DfT), include updated forecasts for passenger numbers, updated noise analysis and a new air quality plan.
The new draft Airports National Policy Statement , which still supports the third runway as the Government's preferred option, will be open to public consultation until December 19.
Around 80% of responses to the initial consultation on the third runway, which closed in May 2017, were positive, having been organised by pro-third runway campaign groups Back Heathrow and Your Heathrow.
Heathrow third runway
The decision to reopen the consultation comes almost a year to the day since the Government announced its support for the third runway on October 25 2016.
The DfT has insisted it is still "on track" to present its final proposals for expansion to Parliament in the first half of 2018.
MPs will then vote on the proposals and, if the scheme is approved, Heathrow will submit a planning application and consult with local communities on detailed proposals.
The airport hopes to begin construction in early 2021, with the runway completed by the end of 2025.
Transport secretary Chris Grayling said: "The case for expanding Heathrow is as strong as ever and we want to hear your views on it.
"This is an important consultation and I encourage everybody to get involved across the UK."
The Government's revised draft NPS says the negative impacts on quality of life, including from increased noise and decreased air quality, from the third runway would be greater than the alternative proposal of expanding Gatwick Airport.
However, the draft goes on to say that "when assessing against the objective of maximising economic benefits and improving competitiveness and employment, the Heathrow [Third] Runway scheme generates the most benefits, as well as producing the highest direct benefits to passengers."
The revised NPS also increased the number of passengers forecast to use the expanded Heathrow Airport by 2040 from 27 million to 28 million per year, while decreasing its estimate for the overall number of additional flights from 125,000 to 113,000 per year.
Cait Hewitt, deputy director of campaign group the Aviation Environment Federation, claimed the "scale of this re-consultation" showed the Government's case for Heathrow expansion is "unconvincing".
She said: "It is difficult to see how this new information can avoid delaying the process, as MPs and the public will need time to understand how the new forecasts impact emissions, noise and the sustainability appraisal of the project.
"These address fundamental questions about the project's viability and have been provided at a late stage in this process."
A Heathrow spokesman said: "The consultation launched today is a key milestone in developing the Airports NPS which will strengthen the policy framework for expanding Heathrow.
"The forecasts show expanding Heathrow, the UK's only hub airport, is even more important than previously realised.
"A third runway will ensure Britain's place in the world as an outward-looking trading nation. That's why the Government has committed to a final vote on expansion in the first half of 2018."
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