London's Gatwick Airport attacks Heathrow expansion report

By Sarah Young

LONDON, July 14 (Reuters) - London's Gatwick Airport on Tuesday attacked the findings of a recent report which recommended its bigger rival Heathrow as the preferred site for a much-needed new runway.

Prime Minister David Cameron has said he will make a decision on whether a new runway should be built at Heathrow or Gatwick by the end of the year, setting the stage for a political battle over an issue which divides the ruling Conservative party.

On Tuesday, Gatwick said it planned to write to Cameron about the issue, saying the government-appointed Airport Commission's pro-Heathrow report was flawed because it underestimated Gatwick's future passenger numbers.

The commission forecast for passenger volumes of 40 million travellers per year through Gatwick by 2024 were wrong because the airport would reach that level this year, it said.

Gatwick also said its economic case was stronger than the commission's report suggested.

The debate over where to build a new runway around densely populated London has been raging for decades with environmental opposition to expanding Heathrow scuppering plans there in the past.

On Monday, environmental activists breached Heathrow's security fences to stage a protest on the runway, causing flight delays and cancellations and illustrating the strength of feeling against building a new runway at the busy airport. (Editing by Estelle Shirbon)