Sebastian Faulks: The BBC binds the nation. Don't condemn it because of one bad day on the Diamond Jubilee

Without Radio 4, the United Kingdom would, I believe, have a collective nervous breakdown

The BBC's coverage of the Diamond Jubilee flotilla last Sunday provoked at first specific criticism, then a wider attack on the organisation. The discontent began with a feeling that the television coverage lacked dignity or factual content, that it relied too much on slightly famous people saying how "great" the atmosphere was. Some critics then talked of "institutional" failings at the BBC, which they would like to see diminished or replaced.

BBC1 apparently decided its lengthy broadcast would come not in the mould of election night but in that of The One Show, its cosy, early-evening magazine. Editors seem to have feared that six hours of watching boats might become dull. It's easy to see in hindsight that the better way to fill the longueurs would have been with more facts – with Kipling's six honest stout serving-men, What and Why and When and How and Where and Who. As Clare Balding, herself part of the broadcast, put it at the Hay Festival: "My belief is always that facts are my friend... And if you ever hear me say, 'The atmosphere here is wonderful' – shoot me." Ms Balding admitted that the coverage of the flotilla had "misfired", and I think we should take her word for it, even if the Monday evening concert was well covered, particularly in the use of helicopter shots to give a sense of place. But there it is. One bad decision, one weak day at the office ...

Only a fool would argue from a single disappointment that the whole of BBC is in some way fatally flawed. However, when tribal politics and business interests are involved, fools abound. There is the further complication of people using criticism of Sunday's broadcast to manoeuvre for the vacant post of director general. The Murdoch newspapers have long been hostile to the Corporation; this position seems based on little more than some lazy idea about the "establishment" and a feeling that any organisation connected to the state may stop Mr Murdoch maximising his profits in a deregulated free-for-all. Right-wing tabloids claim the BBC is biased to the left and is a nest of "political correctness".

Their belief has more justification than the Murdoch one. In more than 30 years of occasional work for it, I have never met a right-winger at the BBC. However, it doesn't follow that a mildly leftish belief prevents you from doing a good day's work or implants bias in your reporting. The only time I have noticed real distortion was in a Radio 4 history of Britain, narrated by Anna Massey, when it came to Mrs Thatcher, whom it dismissed as a minor aberration after whom normal service was resumed. Whatever your own beliefs, that is not what happened.

In 2009-10, I worked full-time for BBC2, making a television series about books. Once, at the end of a long day, I found myself lost in a corridor in TV Centre and asked a staff member the way out. "I can't help," she said. "I'm blind." The entrance lobby sometimes looks like an outpatients' department, so many are those with physical difficulties. You may call this determination to employ across the board "politically correct"; I found it impressive.

Much less so is a kind of bureaucratic nervousness. The Corporation undoubtedly has too many managers, and in the later stages of a programme this can lead to bizarre political manoeuvring. Most of the travel budget on my series had been spent on flying five of us to the foothills of the Himalayas to film a section on Merrick, the repressed homosexual sado-masochist who is the villain of Paul Scott's Raj Quartet. Nine months later, in the edit, I was asked if I could rewrite the section in such a way that it did not mention Merrick's homosexuality. When I had got my fallen jaw back in place, I pointed out that this would be like doing a section on Othello without mentioning that he was a Moor, or from Venice.

I never did understand the reasons for this loss of nerve, but together we overcame it. The most frustrating aspect of working for the BBC was spending most of the lunch hour trying to find a café where lunch was within the permitted £5.50 a head. This was difficult in Mayfair, but I felt the licence-fee payer would have applauded our efforts.

We all have our particular BBC irritations, I suppose. Here are two of mine. Journalists ought to be able to be rude and adversarial with politicians when necessary, but for that to be the default tone for every news interview is wearisome and self-defeating. You and Yours is a consumer programme worth an hour a week in anyone's schedule, but every weekday morning? Surely not, particularly when there is also Money Box and Money Box Live. ("The worst band I've ever heard," as Linda Smith remarked.) But these are only quibbles. In general, the BBC seems to me rather like the monarchy. You would not, as they say, start from here; but just as, against all modern logic, our hereditary head of state has proved to be the envy of the world, so the BBC is in my view the greatest cultural possession this country now has left.

Its importance grows daily, as newspapers lose readers and influence. Without Radio 4, the United Kingdom would, I believe, have a collective nervous breakdown. It is our agora, our parish pump, our water cooler; it exerts a defining and centripetal force on our society. Without its binding coherence, we would be left with the atomised Babel of deregulation, Facebook and "on-demand" streaming, each with our own little headset.

I am writing this on Friday afternoon, having just heard a measured World at One, followed by Richard Holloway's terrific philosophical series Honest Doubt. Have you ever listened to French radio in your hire car? Or watched Italian TV? The Italians ended up making the cable guy their prime minister – and bunga bunga to you too – but give me Desert Island Discs and Test Match Special. And if Radio 4 is our greatest present to ourselves, the World Service has been our gift to the world. Without it, those who lived under totalitarian regimes would have lost hope; imprisoned leaders would not have had the strength to carry on; and millions would never have heard factual news reporting or known that there was such a thing as democracy.

To extrapolate from one substandard day on the Thames the idea that the BBC is not worth having is more than foolish, more than commercially self-interested and politically naive; it is the self-indulgence of spoiled children, ignorant of the privileges their history has showered on them.

Sebastian Faulks's latest novel is 'A Possible Life', published in September by Hutchinson