Business Secretary, Vince Cable, says he is appalled about the size of some loans being agreed by some lenders and has urged the Bank of England to use its powers to intervene.
Vince Cable renewed his stark warnings about the threat to the wider economy posed by soaring house prices in London and the south east amid reports Chancellor George Osborne will tackle the issue in his annual Mansion House speech later.
David Cameron's official spokesman has not sought to distance the Prime Minister from the Business Secretary's remarks over London "draining" the rest of the UK, at a Westminster briefing today.
Instead, he highlighted the PM's earlier comments about the need to rebalance the UK's economy towards areas outside London and the South-East.
"I think the Prime Minister has been clear about the importance of rebalancing the economy," said the spokesman.
London now contributes more to UK GDP than ever before, the Mayor of London said today refuting claims made by the Business Secretary, who claimed that the capital was "draining" the rest of the UK due to its airport expansion plans.
Boris Johnson said: "What a stupefying and ridiculous assertion to make, and this from the Cabinet Minister in charge of supposedly growing the UK economy. He's talking rubbish, I'm amazed and I fundamentally disagree, in fact the opposite is true.
"This city is the motor of the UK economy, and the gateway to recovery across the country, attracting record levels of overseas investment, all of which is helping not hindering recovery.
"Far from being a drain on the rest of the UK London is helping to drive job creation and growth outside the capital as well as in it."
Business Secretary Vince Cable has warned London is "becoming a giant suction machine draining the life" from the rest of the country as he renewed his opposition to a third runway at Heathrow.
The senior Liberal Democrat said the issue of regional capacity had not been sufficiently addressed by a Whitehall-commissioned review of airport provision.
He stood by his determination that expansion of the country's biggest airport - the flightpath of which crosses his Twickenham constituency - "is not going to happen".
Of the three options for expansion presented by Heathrow Airport Ltd in the summer, the Airports Commission is only progressing one of them: the plans for a new runway to the north west of the existing airport.
The other Heathrow idea being investigated by the Commission comes from a pressure group called Heathrow Hub: the extension of one of the current runways.
The proposal is to build a third runway to the north west of the existing airport. It is a different proposal to the one approved by Gordon Brown when he was Prime Minister.
The new runway is further to the west - and anyone who knows this area will work out it brings the runway of Britain's busiest airport into conflict with Britain's busiest motorway, the M25. Look at the plan and you will see the runway is built over the top of the motorway.
That is not unusual. At Paris' Charles de Gaulle airport, a motorway passes under one of the runways in a tunnel. But it does mean this option is not cheap.
Thirty thousand people would be negatively affected by plans to build a new runway at Gatwick Airport, the Gatwick Area Conservation Campaign said.
The campaign group have drawn up a list of possible flight plans, should the project be given the go ahead.
The plans were made in consultation with air traffic control experts, as airports are currently not required to publish flight paths before the runways are built, Brendon Sewill, Chairman of the campaign said.
The plans were made in consultation with air traffic control experts, as airports are currently not required to publish flight paths before the runways are built, Mr Sewill said.
Mr Sewill said a new runway would mean an extra thirty thousand people would be afflicted with noise pollution, bringing the total across the area to 42,000. He said:
"We are not surprised as we always expected matter into focus, but we know we are in for a big battle.
"Howard Davies says we don't need a new runway until 2030 and the plans are not until 2040, but we need to fight like mad to stop a decision that will afflict the whole of Sussex, and much of Surrey and Kent.
"We are agree with national environmental organisations that any new runway anywhere is not compatible with the national enviromental policies.
"Also, the main concern about a new runway in Gatwick is that it would mean the inwards migration of a large number of people from the rest of UK, or from the EU with the need for 40,000 new houses, according to West Sussex County council."