What goes on the campaign bus should perhaps stay on the campaign bus – at least as far as David Cameron’s remarks about closing down the BBC are concerned.

The Prime Minister, amid the rigours of a tough old election campaign, told journalists he was “going to close it (the Corporation) down after the election.”

The story emerged – secondhand – via the venerable Nick Robinson, who was recovering from surgery during the campaign.

My instinct here is that BBC journalists – and I was one of their number for more than a dozen years – are right when they describe this as “yet another of bit of pressure” from a Conservative party which has long viewed the BBC with suspicion and in some cases outright detestation.

However it also rather sounds as though an embattled Cameron was letting off steam rather than making any kind explicit threat.

Nevertheless it would be a mistake to overlook the fact the BBC is approaching negotiations about charter renewal and any kind of comment by the governing party of the day about the broadcaster’s future will rightly be scrutinised to destruction within New Broadcasting House.

Employees there, certainly the journalists, have felt under near constant siege since around the mid-point of the last decade, with several strikes and a long slump in morale the outcome.

First came the devastating findings of the Hutton Inquiry in 2004, which plunged the Corporation into the biggest crisis in its history; there has since followed the seemingly endless rounds of budget cuts borne by those on the shop floor of news.

Taken together these traumas have destroyed confidence BBC producers had in their own ability and produced a drip-feed of hemlock taken via doom-laden emails from senior managers unaffected by mountains of proposed savings.

So the Prime Minister may joke and others around him fire off volleys of complaint in what the tabloid press gleefully calls the government’s ‘war with the BBC’ but oddly there is much the Conservatives would approve of at the Corporation.

While not being an arm of the State the BBC certainly carries with it much of the architecture of State. That is to say the overwhelming majority of senior journalists and bosses tend to be white, middle aged, middle class men and often hail from a public school background.

Their views – hardly surprisingly – reflect much of that and the idea of the BBC being a haven for socialists and subversives is just rubbish, for if there was ever a ‘Left-wing bias’ there certainly is no longer.

Rather the BBC is a socially liberal place and I suspect that is – in a broad sense – the politics of those who work there too. Witness the visit of the Queen back in 2013, with journalists flocking to get near the old dear for a selfie or two.

Indeed those of us who have worked there for any length of time know there is just as much pressure from the political Left as the Right to cover events in an unbiased way. I recall fielding editorial complaints from the likes of David Blunkett, Tory Central Office and the Israeli government.

Mr Cameron and his ilk might be interested to know that if anything there is an in-built editorial bias from the Right because of the way the newspapers – and especially the Daily Mail – help shape the day-to-day agenda at the BBC.

Senior editors plough their way through bundles of the day’s papers before ever committing themselves to covering a story and often end up reflecting what has already been printed, not only in the Mail, but the Times, Sun and Telegraph too.

All of this said I, like Nick Robinson, suspect the BBC will be around for a good long time to come even with John Whittingdale as Culture Secretary. It’s been in bigger scrapes in the past with Tory governments, especially those headed by Margaret Thatcher.

Imagine the UK without the BBC? – not even David Cameron would find that funny.