No conservative admits that actual examples of bias in BBC news are next to impossible to find. Indeed, all conservatives I know turn to the BBC when a major story breaks. BBC bias is mainly Radio 4 bias, and even there it is confined to its cultural chat shows and comedy. BBC managers could deal with it if they moved a handful of biased journalists to The Antiques Road Show, and reminded feature and comedy producers that the rules that cover news cover them too. Conservative writers must exaggerate, however. They must maintain the illusion that the disappointments and frustrations of their readers' lives are the fault of a vast conspiracy.

Look at where the illusion leads. The chairman of the Conservative Party, Grant Shapps, has just said that he is inclined to cut the BBC's licence fee in part because there was a "question of credibility" for the BBC over whether it applied "fairness" to its reporting of politics. In other words, a leading figure in government was telling the state-funded broadcaster that it would suffer if it didn't go easy on the government. This is the language of a dictator or gangster — "show respect or you'll suffer" — and will be heard as such at the BBC.

The assault on the tabloids, meanwhile, has brought Britain as close to state-sponsored supervision of newspapers and magazines as at any time in 300 years. The Conservatives look as if they are backing down. But if Labour or a Labour-Liberal Democrat coalition forms the next government state surveillance will be back. The overwhelming majority in both parties are against free speech for the same reason that the overwhelming majority of conservatives are against the BBC: they believe that the masses are the dupes of the press barons. If they must break the old constraints that limited the state for centuries to allow their side to flourish, they will do it.

The Murdoch press gave them their opening by allegedly engaging in illegal surveillance and harassment on an epic scale, and the police have now arrested more than 100 journalists and newspaper sources. Everyone says that journalists should not be above the law, and, of course, contempt of court law constrains everyone from saying much else.But even in this instance I worry. The mass arrest of journalists ought to set off alarms in a democracy as much as in a banana republic. It would make a refreshing change if commentators on the Left began to ask whether the state was using the hacking scandal as a pretext to frighten off potential whistleblowers.

I used to think that Britain had an extremist intellectual culture — in its press and universities — but a moderate political culture. Continental countries, by contrast, had staid public debates but successful neo-fascist and neo-Communist political parties. I now know that the old distinction cannot hold, and an extremist culture will eventually produce extremist politics. For when broadcasters are threatened by the government, when journalists are arrested by the dozen and when the taboos protecting press freedom are broken by all parties, an extremist politics is what we have.