It’s a few weeks since I was emailed an article by John Ward (also sent to a number of other blog-sites), subsequently published at notbornyesterday.org, alleging the Prime Minister suffers from depression and obsessive compulsive disorder, and that these conditions are being treated with prescription pills.

I decided not to publish, or refer at all to the allegations on Lib Dem Voice. As I explained to John in an email at the time, “without named sources for the story it’s not something we could publish on LDV. I appreciate, given the nature of the story, that having sources on the record is difficult, but still.”

The BBC’s Andrew Marr today felt no such compunction, asking Gordon Brown bluntly: “A lot of people in this country use prescription painkillers and pills to help them get through. Are you one of them?” To which the Prime Minister would have been quite entitled to reply – though of course he couldn’t, as Mr Marr would have known – “None of your damned business.”

There are two issues here. First, was the BBC right to pose the question (and I’m sure the line of questioning was cleared at a high level within the Corporation)? And, secondly, should it matter to us what the Prime Minister’s reply was?

Was the BBC right? Absolutely not. It is possible, of course, that Mr Marr has more credible sources to suspect that the Prime Minister is on prescription pills than blogosphere speculation. I certainly hope he does for the sake of his own reputation as a journalist. If he has such credible sources – more than one, and they are people he believes are trustworthy and in a position to know the facts – then that is a plausibly legitimate story for the BBC to report as news. But that is not what the BBC chose to do. Instead of investigating the story, and presenting it in an objective way to the viewers, it was lobbed like a grenade into a live TV interview.

Defenders of Andrew Marr might well point to Jeremy Paxman’s famous Newsnight encounter with Charles Kennedy in 2002, in which he questioned the then Lib Dem leader about his drinking habits. Mr Kennedy denied the rumours, and Mr Paxman was forced to apologise – though we now know his questioning was both accurate and legitimate.

But there is a difference. When asking about his drinking, Mr Paxman made it quite clear who his sources were: “every politician I have spoken to in preparing for this interview has said, ‘You’re interviewing Charles Kennedy – I hope he’s sober.’” In other words, though the sources were not named, there was a clear explanation to the viewer that this was well-placed, oft-quoted Westminster speculation. Andrew Marr made no such attempt to justify his line of questioning.

Unsurprisingly, the reaction among the more rabid right-wing blogosphere has been scarcely concealed glee that the question has been openly asked. The more thoughtful right-wingers have been more cautious, but I’ve yet to see any condemnation of Andrew Marr’s approach.

Two points here. First, I look forward to this episode being air-brushed out of history the moment the Murdoch Empire / Daily Mail / Tim Montgomerie et al want to indulge in some more easy “the BBC is full of lefty liberals” knocking-copy.

Secondly, I want them to consider for a moment how they would be reacting today if Andrew Marr had asked an equivalent question of a Tory Prime Minister. We don’t have to go too far back in history.

There were many rumours in December 1992 concerning the mental health of John Major, based largely (if my memory serves) on the way his hands trembled when reading a statement to the House of Commons announcing the separation of Prince Charles and Princess Diana. This followed three months of intense pressure for Mr Major, including sterling’s ejection from the ERM, the debacle over pit closures, and the forced resignation of close friend David Mellor. There was talk that Mr Major was on the brink of a nervous breakdown and would soon step down (‘do an Anthony Eden’, as Private Eye put it at the time).

So far as I’m aware from the published history now available, little or none of this was true. Today, though, such rumours would swirl round the blogosphere (though probably not the right-wing sites) – and, if today’s any precedent, soon crop up in BBC interviews. And imagine, just imagine, how the right-wing blogosphere would react to the BBC behaving in such a way if it touched one of their own? The malevolant pleasure some right-wing blogs have taken in amping-up the rumours of Mr Brown’s alleged medical problems has been unpleasant and contemptible.

Let’s consider the second question: should it matter to us what the Prime Minister’s reply was? Assuming Mr Brown was telling the truth – that he is not on prescription pills – then it’s a largely redundant question. But what if he is, but did not feel able, or was not willing, to tell all live on television? Would it matter if the Prime Minister were depressed, and being medicated?

It shouldn’t, in my view. It’s estimated that 15% of the population will suffer a severe bout of depression at some point in their lives. I imagine we all know at least one person who has taken prescription pills to help them through their illness – of those I’ve known, it would never have occurred to me to tell them to quit their job in order to help them through their depression, nor have I ever seen their job performance adversely affected by the anti-depressants they’re taking. I would be far more worried if the Prime Minister were refusing to seek help for a known medical condition, than I am by the idea that he may have sought treatment to help deal with it.

Of course, the only people qualified to make the decision to quit, or not to quit, are Mr Brown and his closest family, friends and advisors. If his feelings of depression were linked to his job as Prime Minister, and the only way he could break the link would be to resign his office, then so be it. I imagine we would all respond with sympathy and understanding to such a decision. However, if his depression were nothing to do with the job – perhaps linked to frustrations with his failing eyesight, or the tragic death of his first child – then resigning would make no difference to his depression, indeed may just make it worse.

There are any number of reasons why the Prime Minister should quit, and just as many again why he deserves to lose the next general election. None of them are related to his health. And in making it an issue on the basis of no evidence, Andrew Marr and the BBC have done a real disservice to serious political reporting.