MPs are twice as likely to back a third runway at Heathrow Airport over Gatwick, according to a new poll on upcoming major government projects.

Two thirds of Conservative and Labour MP's back the Heathrow expansion, gaining more support than the High Speed 2 railway project or third runway at Gatwick.

Support for Heathrow unites MPs across parties, with 90% of MPs believing that "an additional runway in the south east is necessary for the UK to remain competitive as a centre for international business".

While the survey shows that a second Gatwick maintains support, a third runway at Heathrow has more consistent support overall, particularly amongst English MPs outside of London.

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According to the ComRes poll, the majority of MPs also disagreed that an additional runway would prevent the UK from meeting its emissions targets.

This view was supported by the government's Airports Commission, which took the view that a third runway could go ahead at Heathrow as long as it does not breach environmental legal limits.

It is the first poll to be released since Prime Minister David Cameron's decision to further investigate environmental concerns following the Airport's Commission recommendation.

John Holland-Kaye, Chief Executive of Heathrow Airport, said: "Expansion will allow Heathrow to be the best connected airport in the world, as well as the most environmentally responsible.

"As we move in to a new year, this latest polling demonstrates we have majority support from MPs and confirms the breadth of support for Heathrow expansion across the political divide."

Opposition from London MP's against a third runway at Heathrow remains strong however, with MP's Rupa Huq, Sadiq Khan and Boris Johnson campaigning alongside residents.

A decision is not expected until the summer as to where an expansion will take place.