David Cameron to Make Decision on Heathrow Expansion Within Days

David Cameron will in the coming days announce a controversial decision on whether to drastically expand Heathrow airport, in a move that will intensify divisions in the Tory party.

Senior party sources said that they believe a Cabinet subcommittee will this week back plans for a third runway at the airport.

If Heathrow gets the go-ahead as expected, it is believed there will be a series of restrictions imposed on the airport to limit noise and pollution.

It is also believed that there will be a commitment not to build a fourth runway.

However, a number of senior Conservatives including Boris Johnson and Zac Goldsmith, the Tory candidate for mayor of London, will oppose the plans.

Justine Greening, the Tory MP for Putney and International Development Secretary, has promised to continue fighting against expansion at Heathrow.

Mr Goldsmith has previously vowed to quit as an MP and force a by-election in his constituency if Heathrow expansion is approved - although he has said that he will remain in the party.

An independent commission into airport capacity in England earlier this year recommended expanding Heathrow while leaving the door ajar to potentially extending Gatwick.

Sir Howard Davies' commission said that the government should allow Heathrow to expand because this would lead to more jobs, and wider economic benefits than extending Gatwick.

Government sources confirmed that the announcement on Heathrow expansion is due this week.

However, they made clear that it could be delayed because of the Commons vote on whether to endorse air strikes in Syria.

Senior Conservatives are still understood to be lobbying Cabinet colleagues and Downing Street in a bid to convince them that Heathrow is not the best option for expansion.

Ahead of the 2010 general election, Mr Cameron made clear that he would oppose a third runway.

He has been repeatedly reminded by critics of Heathrow of the "no ifs, no buts" promise to block expansion at the time.

TV reporters have even attempted to find the tree Mr Cameron planted to prove his dedication to opposition in recent years, but have been unable to find it.

Despite the stance, Mr Cameron's allies have become increasingly convinced of the need to expand Heathrow.

Mr Johnson is a vocal opponent of Heathrow and believes that a new hub airport should be built elsewhere in the South East of England.

His criticism was mocked by George Osborne -- his Tory leadership rival believed to be an advocate for Heathrow -- earlier this year at the post-election Budget.

The Chancellor made a joke about remembering a time when airplanes flied "freely over the skies of west London" as he announced extra funding for a Battle of Britain bunker.

Senior Tory figures have repeatedly said a decision on the airport expansions was to be made before Christmas.

However the circumstances of how the government will secure parliamentary approval for their choice is still being debated.

Because the infrastructure project will not necessarily need new legislation there is no necessity to get their decision through the House of Commons, according to Tory sources.

However given the political sensitivity around the decision it is understood government figures believe they will have to hold some form of vote for MPs.