Former Tory MP Zac Goldsmith has accused the Government and Heathrow Airport of having a relationship that "borders on the corrupt".
Mr Goldsmith, who resigned last week as an MP in protest at the Government's Heathrow expansion plans, forcing a by-election which he is fighting on a campaign of opposition to the move, said the interaction between the airport and Whitehall was "rotten".
He told LBC: "I think the relationship between Heathrow and Government is bordering on the corrupt.
"And I'll put it into context.
"A year ago I was lobbying the infrastructure minister Lord Deighton, and I was lobbying him on this issue of Heathrow expansion, and he responded very politely and took a few notes.
"A few months later he was the chairman of Heathrow.
"And that is true all the way through.
"You've got the former head of comms at Number 10, now the head of comms at Heathrow.
"Former head of comms at Heathrow now the head of comms at the Department for Transport, and I could spend an hour giving you other examples.
"I think there is a problem. It's not a Conservative Party problem. This was true under Gordon Brown, and the Tony Blair government before that. The relationship between the two is rotten.
"The revolving door is spinning wildly, and sometimes it is hard to know where Heathrow ends and Government begins.
"And that's why you've always had this default position in favour of Heathrow.
"Why is it that we have this institutional obsession with a solution that is a non-solution and can't be delivered? It's very hard to explain, except through the lens of corrupted relationships."
Asked about Mr Goldsmith's allegation of corruption, a Downing Street spokesman said: "We reject that entirely."
The Number 10 spokesman added: "The Airports Commission was absolutely clear that Heathrow is the best option for airport expansion in the South East.
"We took our time to look at that report, we commissioned extra work to go alongside that.
"That has been very carefully scrutinised and we are absolutely of the opinion that Heathrow is the place where airport expansion should take place."
A spokeswoman for Heathrow Airport said: "This is absolutely untrue.
"The Government's decision follows the most in-depth study of aviation expansion in a generation, the independent experts of the Airports Commission unanimously and unambiguously supported Heathrow's plans for expansion.
"After two-and-a-half years, and a £20 million study, the Airports Commission confirmed that expanding Heathrow would have the biggest economic benefits for the UK and can be done while reducing noise for local communities and in accordance with EU air quality law."