Heathrow free vote would be 'a fudge and dodge'
Any plans to give ministers a free vote on Heathrow expansion would be "a fudge and a dodge", former minister Grant Shapps has said.
His comments came after Channel 4 News reported that a document carried on the London Underground by a civil servant was filmed by another passenger.
It discussed the "potential waiving of collective responsibility" ahead of a decision on airport capacity.
The government has said it will make a decision on Heathrow "in due course".
The Airports Commission recommended in July last year that a third runway should be built at Heathrow.
However, the Department for Transport said further investigation into noise, pollution and compensation would be carried out before a decision was made.
The document photographed on the Underground was a printout of an email to Sue Gray, the director general of the Cabinet Office's propriety and ethics team.
It states that lawyers and members of the Cabinet Office's economic and domestic affairs secretariat "are seeking specific input from us on how to handle potential waiving of collective responsibility".
The document suggests that "one route for waiving collective responsibility would be a free..." with the next word hidden by the thumb of the woman holding it.
The sentence continues "... allowing ministers to speak against the government's position in the House".
Mr Shapps, a former international development minister who now heads the British Infrastructure group of MPs, told the BBC that the government should send "really positive signals that we're open for business".
He added that the handling of ports and airports was "about the most important way that you can show that you're looking outwards, going to be internationalist about this".
"And I think to come up with some fudge that said, well some Cabinet ministers won't need to vote on this, in fact could even argue the other way, would be entirely wrong because it would be leaving the future of our infrastructure pretty much to chance."
Shadow chancellor John McDonnell, whose Hayes and Harlington constituency would be affected by expanding Heathrow, said any proposal for the site would be defeated in the courts because of the environmental concerns.
He told Channel 4 News: "The government on this issue seems to be in absolute chaos. On free votes, it's usually for major constitutional matters or moral conscience issues or an individual MP will be given a waiver because of their constituency interests.
"I speak as the constituency MP for Heathrow and I would have expected a proper debate and then a vote. To have a free vote in this way means that [for] virtually every major infrastructure people will be demanding a free vote and now, on other issues, why not grammar schools, why not every other major policy issue?"
Liberal Democrat leader Tim Farron said suggesting there could be a free vote on Heathrow was "farcical".
He added: "This is a huge decision and the Conservative government has to make a collective decision and take full responsibility."
A government spokesman said: "The government remains committed to taking a decision on airport expansion and delivering additional runway capacity as planned by 2030. We will set out next steps in due course."