Theresa May has defended the cabinet secretary after it was reported that he told ministers not to make public comments about a third runway at Heathrow.
The government is set to respond to the Davies Commission on aviation by the end of the year, after the commission's independent report backed a new runway for the airport.
According to the BBC, Sir Jeremy Heywood wrote to ministers ahead of party conference season advising them not to make new comments about Heathrow ahead of the official response in case an intervention triggered legal action.
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An unnamed cabinet minister told the broadcaster that the move by Heywood was "unprecedented", while Tory peer Lord True said Heywood "fancied himself a bit of a politician".
But, speaking to the Today programme, home secretary May backed the principle of the advice, while refusing to "comment on leaked documents".
May said: "I am very clear of the importance of cabinet ministers not making comments on this particular issue such that when a decision is taken – whichever decision is taken at the end – people can complain and say it was somehow it was an a priori decision and therefore judicially review it.
"This is an important decision and it’s right that cabinet ministers are not speaking about it publicly until a decision is taken."
She added: "I think you are making rather a mountain out of a molehill here."