Heathrow campaigners this week posted letters to David Cameron thanking him for keeping his promise not to allow a third runway at the airport - for now at least.

Hundreds of protesters opposed to expansion of Heathrow have written to the prime minister expressing their gratitude after he announced last week that a decision would be delayed six months to consider environmental concerns.

Their missives urged him to stick by his pre-election pledge in 2009, when he declared 'no ifs, no buts; there will be no third runway at Heathrow', and not to break it when the decision over whether Heathrow or Gatwick should get an extra runway is made next summer.

On Friday (December 18), three campaigners posted letters to Mr Cameron via a post box in the heart of Westminster.

John Stewart, chairman of anti-Heathrow expansion group HACAN, said: " These letters are yet another indication of how strongly people feel about a third runway.

"We urge David Cameron to keep his promise in 2016."