Senior Tory Boris Johnson today challenged his party's manifesto pledge to build a third runway at Heathrow Airport.
Mr Johnson, who hopes to be re-elected as Conservative MP for Uxbridge & South Ruislip was meeting voters in the Labour-held marginal of Brentford & Isleworth.
The former London mayor told ITV News the runway would be 'very difficult to deliver' because of noise and pollution concerns.
His comments were echoed by Shadow Chancellor John McDonnell. Both men represented constituencies affected by aircraft noise.