Everyone loves a conspiracy theory, but according to author and former North Yorkshire vicar, Graham Taylor, The Da Vinci Code is pure fiction - although the Holy Grail could be in Yorkshire.

IF YOU want to tell a lie then tell a big one. That's the best way to start any book, make the story so fantastic that it will set people's minds on fire and then instead of them thinking it's fiction throw in a few facts that they can check out and suddenly you have the makings of a great conspiracy. Add to this a fast moving plot, great characters and amazing settings and very soon you will have a worldwide best seller. Give it a mystical name and you will have The Da Vinci Code.

It was April 2003 when my American publishers sent me a copy of the book. I was asked to read it as they said it would be 'big' and every chat show host would ask me what I thought of it. They were right. It was a story that I had heard many times before. Jesus the Son of God had a crush on a hooker named Mary of Magdala, did the business and had a child to her. The Holy Grail wasn't the chalice of the last supper searched for by the Monty Python knights; it was in fact the true blood - the Royal bloodline of Christ.

Any conspiracy fan will know that this tale has been around a long time. Rumours of the story surfaced in the 1950s. Then, the conspiracy was that the Catholic Church had kept the true facts about Christianity secret by using terror tactics and that they had something very sinister to hide. For those who went along with this, the secret was that Jesus was not the Son of God - he had a daughter called Sarah and his descendants became the Kings of France. The uber-secret organisation in charge of this deceit was The Priory Of Sion. But this allegedly ancient order had, in fact, not been founded until the 1950s and wasn't ancient at all.

Later, the BBC produced an excellent documentary on the subject and blew the theory, exposing its basis as false and telling the world that the man who started the rumours had been in prison for deception. From then, Jesus became the target of the conspiracy nuts, set to expose Christianity as a fraud and the Catholic Church as being worse than the Mafia. There have been countless books, documentaries and articles that have hashed and rehashed the story again and again.

The thing is that everyone loves a conspiracy. There is nothing more exciting than thinking things are other than they seem. I am currently writing a book about a group of businessmen who run the world and hold the key to political power. It's a book based on fact and can be easily checked out. I sat and listened to David Icke talk for hours on the subject and he had me convinced. It's based on the premise that 13 men control the financial and economic future of the world. Already, everyone wants to know what it's all about. Is it based on fact? - slightly. Will it be a best seller? - possibly. Is it true? - perhaps.

But it took a good fiction writer to take the story of the Holy Grail and give it what it needed to succeed - a very good plot, fast moving action, a sexy heroine and a benign hero. Dan Brown has managed to do what no other has - he has turned a boring subject of Gnostic gospels, codices and numerology into something that everyone can easily understand and crack the plot for themselves. In total, a brilliant work of fiction.

What we have to understand is that The Da Vinci Code is just that, a work of fiction. Forget the front page where Brown talks about the facts, the words on his website say it all: "My belief is that the theories discussed by these characters may have merit."

The key here is the word theories. A theory is something that hasn't yet been proved one way or the other. The theory of The DaVinci Code has never and will never be proved because it is a work of fiction. Historically, it is incorrect and theologically unsound. It is a theory based on Jesus having it off with a hooker named Mary. Again this isn't true.

Jesus did know Mary of Magdala; she did exist and is a person recorded in historical documents. Mary was the woman Jesus healed of 'demons'; she followed him in his work and was a witness of the crucifixion. She saw him being buried and was there when the tomb was found to be empty. There is no reference to Jesus having sexual relations with her and I am sure that if he had, then his enemies would have been sure to put it about and publicise it. After all, they called him mad and a frolicker with sinners, but knocking off repentant call girls was something they couldn't pin on him. There is not one shred of evidence to say that they were married and the idea is fanciful.

Christianity has had too many detractors for secrets that are espoused by Brown to be secret for very long. There are no hidden codes in the pictures of Da Vinci. These would have been discovered long ago. The history of the Mona Lisa is extremely well documented and there are no missing links. All that is promoted in the book in regards to secret knowledge is just part of the fantastic, but fanciful, plot. I will certainly be out there getting it on DVD and watching it again and again as pure entertainment. It is not something that will rock the foundation of the Church, as it would need something far more powerful than a modern novel to do that. Two thousand years of criticism has failed to destroy the Christian faith as will the sale of a few million books.

But for the Grail hunters among you, a possible theory is that the Grail was the cup that Joseph of Arimathea used to collect the blood of Christ. It most probably fell into the hands of the Templar Knights and was brought to England.

If this is true, I'm convinced it will just be an earthenware pot, not a golden chalice. Its resting place is likely to be, not Rosslyn or Glastonbury, as they were just smokescreens.

Instead, if an old Yorkshire poem is to be believed, it could be hidden beneath an old Templar Church somewhere in the North of England. I'll let you decide...

Beneath the bell, upon the moor

The cup of Christ be seen no more

There in the pit, its resting place

Gathers dust no more in haste

High on the cliffs in wind and strife

The chalice of the Saviour will bring life.

*GP Taylor's latest novel, Tersias, is released in paperback in June. The sequel to Shadowmancer - The Curse of Salamander Street is published in hardback in September.