As best as anyone knows, governments cannot actually go to war with the BBC.

Sending in the SAS to take control of Antiques Roadshow involves practical difficulties. As for "firing a shot across the bow" of the Corporation, think of the mess in London's Portland Place. Mind how you go, as some traffic warden is bound to say, with that artillery.

The appointment of John Whittingdale to the Department of Culture, Media and Sport has nevertheless put some newspapers in a martial mood. They are on his side. Or rather, they are on the side they presume is being led by the former chairman of the Commons culture committee in a settling of accounts - and words to that effect - with the BBC.

It is, for now, a merry sort of warfare. Newspapers owned by people with a direct commercial interest in hobbling the Corporation think they have a Tory government free to do the right Tory thing where the state broadcaster is concerned. Because Mr Whittingdale has called the licence fee a poll tax (which it is) and questioned its future, commerce and ideology are in happy union. The BBC is to be taught a lesson.

Some motives are so obvious they hardly need to be stated. For Rupert Murdoch, the former-Australian with vast British press and TV holdings, whatever is bad for the Corporation is good for business. It is as simple and as a brutal as that. Alongside him stand the owners of the Mail and Telegraph groups. With a slightly different mix of commercial and political desires, they too regard the BBC as an infernal obstacle.

They point to a left-wing bias at the Corporation. Anyone actually on the left, even to the slightest degree, wonders what on earth they're on about. Unless there is some secret channel available only to Conservatives, we see a BBC that defers to establishment opinion. If David Cameron was indeed "outraged" by allegedly partisan election coverage, there's something up with his hearing.

It's not new. A Tory obsession with the "pinko" BBC goes back at least as far as the Thatcher era. Professor Jean Seaton even gave her recent (official) history of the Corporation in those years the sardonic title Pinkoes and Traitors. For just as long, and all through the campaign, Labour people have detected a right-wing bias. Witnesses to the Scottish referendum saw something else again: a state broadcaster with British in its name making repeated assumptions about political legitimacy.

Defenders of the BBC have an old strategy for dealing with all of this. If the BBC has no political friends, they say, it must be doing something right. This is a mistake. First, it assumes that anything attacked from left and right must be in the centre, and that being in the centre is always good. But "centrist" is just another political choice, and about as much use in a fight for institutional survival as the bogus idea of impartiality.

Secondly, the BBC, snared in righteous self-regard, does not often report why it has so many enemies, or what motivates those enemies. The duty to report fairly is neglected. The truth is that politicians like Mr Cameron have no wish to destroy the broadcaster that gives readers of the Daily Mail, and millions besides, their dose of Call the Midwife. The desire to control the BBC, on the other hand, runs deep.

Mr Whittingdale's job will be three-fold as he prepares for the renewal of a BBC charter that will expire in December 2016. First, put a lid on the licence fee and keep most of the customers satisfied. Secondly, ensure that the Corporation's journalists watch their step for a couple of years. Thirdly, clear some commercial space for those media rivals of the BBC who have been such loyal friends of the Conservatives. It will not be "war" - that would look vindictive - but it will be a hard-nosed, populist campaign.

The BBC's problem is that it has a case, or several cases, to answer. Budgets have been cut hard. Journalism, in particular, is showing the strain. Yet the Corporation is still by far the most dominant force in news gathering. On election night, ITV had 650 staff at work; Sky 500. The BBC marshalled around 2,000 people to dominate the ratings. Its critics question the scale of that subsidised effort to wipe out the competition. Those with money at stake ask, as they always ask, why the Corporation should be chasing ratings at all.

The question is acute for the newspaper industry. The BBC's sprawling online effort, covering all the nations and regions of Britain, comes at an annual cost of several hundred million pounds. It is a hugely impressive service available to all. But it is also a direct, growing threat to local newspapers. You don't have to be the foreign owner of a media group to make a distinction between what the BBC can do and its reasons for doing so.

As he readies for phoney war, Mr Whittingdale has a lot to chew on. When the headlines have faded, he could ask himself why a government minister should have any right to interfere with a broadcaster whose independence is guaranteed, in theory, by charter. Mr Murdoch will not be interested in such niceties, but the point is important: you cannot talk seriously about bias unless you talk about independence. The alternative, on Planet Murdoch, is Fox News.

If the new Culture Minister is being more serious than the headlines, he could also ask existential questions about the BBC. That touches on the licence fee. Put aside the issue of journalism and try an experiment. Run through your digital planner and ignore all that is BBC. Ignore the QI reruns, the Dr Who repeats, the Sherlock, Wolf Hall, Hairy Bikers, Call the Midwife: what remains? A handful of big American series and a lot of filler. A fee of £145.50 begins to sound cheap.

The BBC can do its own boasting. What confronts the minister and gleeful Tories is a reality. The Corporation is not occupying a commercial space that would be filled with the bounty of a free broadcasting market. Ben Stephenson, stepping down as BBC head of drama - to work in the United States - made the case this week. The market, he said, is not going to "fill the gap" if the Corporation is forced to shrink again. Jobs and drama output alike will be reduced.

The fundamental problem for the BBC is that loyalties have fragmented much as audiences have fragmented. In Scotland, thanks to the referendum, a great deal of trust has gone. Tories who see pinkoes and opportunities at every turn might settle for a subscription-based National Trust home for public service broadcasting, but little else. Labour has its own complaints. The BBC is no longer second on everyone's list, after the NHS, of precious institutions.

That being so, Mr Whittingdale might care to recommend the devolution of control over broadcasting to Holyrood. Why would that offend free-market ideologues who hold the BBC in contempt? You can judge how and why the Corporation still matters to Britain by a prediction: it won't happen.