(Adds chairman comments)
By Sarah Young
LONDON, July 14 (Reuters) - London's Gatwick Airport said it was still in contention to be chosen as the site for a much-needed new runway in southeast England, dismissing a report recommending expansion at Heathrow as flawed and stoking a political battle over the issue.
Prime Minister David Cameron has said he will make a decision on whether a new runway should be built at Britain's largest airport Heathrow or Gatwick by the end of the year, an issue which divides the ruling Conservative party.
Heathrow was recommended as the site for a new runway by an independent government-appointed commission earlier in July, but Gatwick said on Tuesday that the numbers in the report were flawed and it would be writing to Cameron.
"We are absolutely sure that what they've finally settled on does not make sense, and we will be putting that point as strongly as we can to government," Gatwick's chairman Roy McNulty said at a press briefing.
Gatwick's claims will give ammunition to a group of high-profile Conservative politicians, including Mayor of London Boris Johnson, who have publicly expressed their opposition to an additional runway at Heathrow.
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, Gatwick said.
McNulty said Gatwick, Britain's second busiest airport, had raised its objections to the figures the commission was using two years ago.
The debate over where to build a new runway around densely populated London has been raging for over 25 years with environmental opposition to expansion at Heathrow scuppering past plans there.
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 airport.
The Gatwick chairman added that the commission's report had inadequately addressed environmental concerns.
"We think that they haven't given sufficient consideration to the environmental impacts, which is the thing that has always stood in the way of expansion at Heathrow, and probably still stands in its way," he said.
Editing by Estelle Shirbon and Keith Weir