A London MEP today said Ann Keen MP should resign from Government if she is strongly opposed to a third runway at Heathrow.

Dr Charles Tannock, a member of anti-expansion campaign group Hacan, made the comments as he visited residents in Osterley with shadow transport secretary Theresa Villiers and Conservative parliamentary candidate Mary Macleod.

Ms Villiers praised campaigners in Hounslow for leading the fight against a third runway, saying: “I would emphasise the hugely important role your councillors have played in shaping the debate, I took those views to David Cameron and we came out against the third runway.”

Mrs Keen, MP for Brentford and Isleworth, has previously insisted she has been opposed to Heathrow expansion for many years, but residents accused her of not being vocal enough in her opposition.

Yvonne Minnis, 77, of Downs View, Isleworth, said: “We have no faith in her whatsoever.”

Mrs Keen said this week: "Opposition to the third runway is now moving into the planning stage and I will be demanding the very highest standards of insulation and air-conditioning for all schools affected by aircraft noise and pollution in my constituency, as well as the maximum help for residents."

She said she was “really puzzled” by Tory policy on Heathrow, saying that using it to display their “green” credentials contradicted London Mayor Boris Johnson’s proposal to build an airport in the Thames estuary.

She added: “While they don't appear to be against airports per se, there is a suspicion their motives on the third runway debate are to make political capital when it suits them - especially as David Willetts was enthusiastic about Heathrow expansion when he appeared on Any Questions at Cranford Community School last year.”

Ms Villiers hit back saying: “She didn’t vote against it [the third runway] in Parliament and she is a member of a Government that is determined to make it. I don’t really understand her position.”

Conservative MEP Dr Tannock added: “She should resign from Government if she feels that strongly against it.”

Mrs Keen was unavailable for comment on calls for her to resign.