There has never been anyone in broadcasting like Bill Heine and we can be pretty damn certain there will never be again.

For if you think about it, there is not much chance of anyone else shattering the roof tiles of their home with a giant shark seemingly dropped from the sky. And there’s even less likelihood of the BBC giving someone their own radio talk show on the back of attention seeking on such a monstrous scale.

But exactly 20 years after pole vaulting himself on to the Radio Oxford airwaves on the back of his shark, Mr Heine, like the 25ft fibreglass work of art at his house in Headington, is still with us - both of them now firmly established as provocative additions to Oxfordshire life.

The American reckons to have totted up a remarkable 17,000 hours of broadcasting, ever ready to challenge and coax opinions from Oxfordshire’s good and great, obscure and obsessive, caring and cringe-making, loveable and lunatic.

Mr Heine readily recognises that he is one Yank in Oxford who certainly got lucky when Auntie Beeb decided to take him in hand as an infant broadcaster on Halloween 1988, putting him behind a microphone for a lunchtime phone-in programme with a wing and a prayer, without any experience, training or parachute.

“That was probably the last time the BBC ambushed someone in the street and made them overnight into a main sequence presenter in the daily schedule,” he now recalls.

But Auntie Beeb made some attempt to cover her back.

“I got a one paragraph letter that was the only ‘contract’ I had for the first five years. It said we would ‘try this out for two or three months. Of course, we have to point out you could be fired at any time because obviously we don’t want to have someone on air who is a liability’.”

Oh, how the BBC must today wish that they had had such an arrangement with that one-man licence payers’ black hole, Jonathan Ross.

It seems two liquid lunches set Mr Heine on his way.

The first was at a house-warming party, when, after four bottles of Veuve Clicquot, he and the sculptor John Buckley came up with the crazy shark idea as their madcap response to the craziness they felt to be all around them, with the Chernobyl nuclear disaster and US planes flying from Upper Heyford to bomb Tripoli.

Down the years, his explanation has come to make more sense.

“We wanted to ask a simple question. In our every day lives, how safe are we from the results of decisions by people in power? And we wanted to ask in a way that involved the public, caught them off guard and made them smile.”

Catching people off guard was a quality that the then boss of BBC Radio Oxford liked.

Mr Heine was taken to lunch and offered a job.

“This is the beginning of something big,” he was assured, with the additional promise of lucrative supermarket and shopping mall openings to follow. “This is why we’re going to pay you peanuts,” the BBC man cheerfully added.

“They just don’t do that anymore,” Mr Heine told me, when we met up for a rather less boozy lunch, around the corner from the BBC studio in Summertown.

“I hadn’t been trained. They didn’t know what would happen. But that was the fun, the risk, the rawness. When I started out, I was a different voice. I was the voice from the street.”

It was to be the start of a 20-year conversation that is showing no sign of drawing to a close: the conversation between Bill Heine and Oxfordshire.

There is no doubt that there have been times when the BBC have bitterly regretted the decision.

He was once sacked three times in a single afternoon, something not even Jonathan Ross and Russell Brand have managed between them.

His crime was nothing to do with messages on answer phones, but to invite a university psychologist along to give a live counselling session, with an actress playing his client.

Radio Oxford’s managing editor returned from a long lunch to find Bill’s guests resorting to primitive groans, moans and grunts.

He acted altogether more decisively than Radio 2 chiefs in recent days.

In his earphone Mr Heine heard the fateful words: “Heine you’re fired. Get this crap off air. You’re dead meat.” But ‘the silver fox’ finished the programme and somehow talked his way out of the guillotine.

So how did a Yank at Oxford fly below the radar of the BBC establishement and manage to stay on the air for 20 years?

To answer that question he has written his first book Heinstein of the Airways: Discovering a Parallel World Within Oxford.

When word first spread that the Radio Oxford man was working on a book, many assumed it would tell the story of his boyhood in Illinois, his time working in the home of Robert Kennedy at Hickory Hill in Virginia ( where he once helped set up a piano for Roberta Flack) and his time with the Peace Corps in Nicaragua and Peru.

Then there was his time at Balliol College and years running the Penultimate Picture Palace and Moulin Rouge cinemas to look forward to, along, of course with his epic battle with those spoilsport Oxford councillors who believed the shark’s appearance in New High Street signalled the dawn of planning anarchy, if not the disintegration of society.

But it turns out Mr Heine’s mission is rather to offer an up-close look at the underside of his adopted city.

“I wanted to produce a portrait of Oxfordshire and the people who live here. Phillip Pullman created a parallel universe outside of Oxford, I’ve looked at what we have right here inside Oxford and found it.

“So many people have allowed me into their lives. People have expressed raw honesty, telling me about their hopes, fears and vivid experiences, which I did not want to disappear into the ether. In a sense Heinstein of the Airways is a tribute to them.”

But the Heine universe certainly rivals Pullman’s for darkness, with chapters dealing with paedophiles, urban terrorism, sexual abuse and foreign prostitutes, and a contract that was taken on the broadcaster’s life.

For the first time he reveals the details of a death threat that was to deeply affect him, even changing his view of Oxford itself.

It resulted from an newspaper article that he wrote about a child abuser. The man responded to the piece by putting up money to have Mr Heine shot.

“Why was I in this situation?” he now reflects. “Because I wanted to stop other people from becoming victims of a paedophile.” How do you live with a death threat? It affects the people you love, the person you want to be and the people who could be at your graveside. Every aspect of your life is under scrutiny,” he writes. “You pare things down to the core, to what really matters; and as with so much of this story it comes down to children. But now it was my own 11-year-old child. It was the bloom on his cheek in the morning when I woke and he was still asleep. If someone shot me what would that do to him?”

Oxford itself was to become a dark place in his troubled mind.

“The friendly familiar face of the city I knew and loved altered. Beautiful streets suddenly became dangerous. My Dr Jekyll city was turned into Mr Hyde.”

If he fell foul of criminals, Mr Heine also failed to endear himself to the police, with Thames Valley Police refusing to speak to him for two years, even denying him travel information.

It all came down to an interview with a senior firearms officer on the need to be vigilant with guns that badly backfired. The officer had mistakenly left one of his demonstration guns in the BBC reception area.

Instead of having a quiet word afterwards, Bill chose to inform his embarrassed guest about the discovery live on air, having first maximised the humiliation by inviting the officer to do an audit of the firearms he had brought in. There were to be bitter accusations of a ‘stitch-up’.

The broadcaster remains, typically, unrepetant.

“Sometimes you have to cut the cards and deal, on your own, because there is no time or opportunity for the luxury of consultation.”

But we can be pretty sure officers relished the chance to arrest him for sedition before throwing him into a padded cell at Oxford Prison, even if it was only for a fundraising Children in Need stunt. Having his clothes ripped off and being put in straitjacket was a little too close to the bone, even for Children in Need, from the presenter’s point of view, however.

On Friday, he was to enjoy altogether warmer hospitality in the Ashmolean, where guests were entertained by the New College Choir and band The Epstein, at the launch of his book. Plenty of Oxford universes collided as guests mingled.

The many shark watchers in attendance, learnt they can sleep easy, happy in the knowledge, that the BBC presenter is already working on a second book.

And, yes, it will be about that other great survivor in the Bill Heine story, still loved and loathed every bit as much as its creator, and equally impossible to ignore.