A public consultation into the planned third runway at Heathrow Airport has been reopened due to new evidence.

The Department for Transport (DfT) published a series of fresh reports into the impact of expanding the west London hub, including updated noise analysis and a new air quality plan.

A consultation on the draft Airports National Policy Statement (NPS) - which sets out the Government's support for the Heathrow project - initially closed in May, but it has now been reopened until December 19.

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 DfT insisted it is "on track" to publish final proposals for expansion in the first half of 2018 for a vote in Parliament.

If the scheme is approved by MPs, 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.

Cait Hewitt, deputy director of campaign group the Aviation Environment Federation, claimed the "scale of this re-consultation" shows that the Government's case for Heathrow expansion is "unconvincing".

She went on: "It's 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 the process."

mfl 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."