Pressure is mounting on the BBC journalist Andrew Marr to apologise after he asked the Prime Minister whether he had been taking any "prescription painkillers and pills" under stress.
I can exclusively reveal that, in addition to widespread condemnation, several Labour ministers and hopefuls have declared their intention to boycott the show until he apologies.
Marr has come in for heavy criticism because he has been seen as legitimising, as Peter Mandelson said, internet smears and rumours by "extreme right-wing people". The narrative that Brown is "bonkers" or "mental" and therefore unfit to lead the country uses prejudice against mentally ill people to take down the Prime Minister through character assassination.
At the Labour party conference fury at Marr's question was everywhere. Jon Cruddas, a leading lefty, described it as "absolutely disgraceful" and said he would happily boycott the show until Marr apologised.
David Lammy, the minister for higher education, joined the chorus of boycotters, saying he was disgusted by the breach of professionalism. Ian Martin, another minister, also put his name to the list. He had earlier been snapped engaging in an angry exchange with Marr. The Labour PPC for Streatham, Chuka Umunna, also intends to boycott the show, we can reveal.
Peter Mandelson only said he "would consider" the idea of a boycott, but condemned Marr in very strong terms.
What is unprecedented about the backlash is that so many journalists have also chosen to criticise the BBC interviewer.
David Hencke, the former Guardian Westminster correspondent who is now at Tribune, said it was "below the belt". Cathy Newman, political correspondent for Channel 4 News, said: "Journalists should be dealing in facts, not rumours."
Adam Boulton of Sky News argued that Brown had already been asked whether he was taking any pills by lobby journalists, and a denial made it difficult to justify further questions without new evidence.
On the principal point as to "Should interviewers be able to ask questions about the physical state or health of the Prime Minister?" I think they should. So in that sense I don't think it's gratuitous. My personal view is that on that specific point, I felt, and I think most of us working at Westminster felt, that question had been asked and answered, and we all felt that on [the grounds] that it had been denied, and on the level of evidence we had, there was no basis to take that further.
The most stinging rebuke  came from a former colleague of Marr's at the BBC, Nick Assinder, who has worked in the press lobby and across the media industry covering politics. He said:
So, here is a classic example of a dark, unsubstantiated rumour about the Prime Minister's personal life that owes its existence entirely to a single blog. The fact that it fitted the narrative about Brown's character only ensured it gained even greater exposure . . . No one is suggesting this was a deliberate plot like Smeargate. If anything, it shows such co-ordinated campaigns are unnecessary: a single blog posting can do the trick. Nonetheless, Damian McBride would have been proud.
The Spectator magazine's political editor, James Forsyth, also called it an "inappropriate question".
In his defence, Andrew Marr told the Guardian: "It was a tough question and I clearly thought carefully before asking it. I decided it was a fair question to ask or I wouldn't have asked it."
He said he had no intention of apologising, particularly as no one from the government had registered a complaint.
But his question, asked abruptly, clearly surprised Gordon Brown, who said: "No. I think this is the sort of questioning which is all too often entering the lexicon of British politics."
But with more than a hundred complaints from viewers to the BBC over the incident, a growing chorus of MPs joining a boycott, and disgust from across the media, Marr may yet realise that giving voice to unsubstantiated internet smears was perhaps not his finest hour.