A third runway at Heathrow is the most popular option among MPs for solving the air capacity squeeze in the southeast of England, according to a new poll.


Almost half (46%) of MPs strongly back or tend to support expansion at the hub airport.


But only 16% support London mayor Boris Johnson’s vision of a new London gateway airport in the Thames estuary.


Heathrow was four points ahead of Gatwick, which was backed by 42%, and seven points clear of Stansted, supported by 39%.


The ‘Boris Island’ scheme was the least popular option among the 93 MPs questioned by Ipsos MORI for the Evening Standard newspaper in London.


More of both Labour and the Conservatives support Heathrow expansion than oppose it.


The research found that more Conservative MPs support the expansion of Heathrow than oppose it – some 47% support it versus 39% against. Support was even higher in Labour, at 50%. But 70% of Liberal Democrats opposed it.


An estuary airport had the highest levels of opposition of the four options – Conservatives were 48% against; Labour 64%; and Liberal Democrats 80%.


But Heathrow had the second highest level of opposition, at 35%, indicating it raises passions on both sides.


Ipsos MORI Reputation Centre director Carl Phillips said: “The idea of a London gateway airport has been disregarded by the majority of MPs – clearly the mayor has his work cut out if he wants to win support for a new airport.


“Meanwhile, the option of expanding Heathrow sees MPs polarised, especially across the Conservative benches. Labour MPs are the most likely to support a third runway, but only half support it, while the Liberal Democrats are vehemently opposed.


“By contrast, while the idea of building additional runways at Gatwick and or Stansted attracts a comparatively strong level of support across the House, there is no majority view.”