The Cabinet Secretary, Simon Case, the country’s most senior civil servant, had told all ministers they should “not take part in the public debate.”
Mr Streeting’s repeated public opposition, including asking officials to examine the costs to the NHS of implementing any change in the law, has provoked private and public irritation from some of his Labour colleagues.
One cabinet source said it was “ridiculous” to expect the health secretary not to give his view.
On Friday morning, the prime minister and the health secretary spoke about it face-to-face, a conversation, one source told me, amounted to a telling off for Mr Streeting.
Neither Downing Street nor the Department of Health deny the meeting took place, with another source insisting afterwards there was “no outstanding issue” between the two men.
Those around the prime minister also acknowledge that it is reasonable that both the health secretary and the justice secretary would face more questions than most on the issue, given they would be responsible for implementing any change in the law.
But the fact that both are opposed to such a change highlights the tensions this is causing within government – could either, realistically, implement such a colossal change, weighted with moral considerations, which they personally opposed?
And what of the prime minister’s position? And how awkward could it be if he finds himself on the losing side of the argument?
It has provoked some pretty searching conversations at the top of government, I am told, about how best to handle it – to minimise the prospect of what some see as an “unnecessary mess".