The Alexander Cipher is a fast-paced modern-day story about the search for the tomb and treasures of Alexander the Great, who died in 323BC having ruled an empire that stretched from Greece to the Indus Valley and Thrace to Egypt.

Mixing historical fact and fiction, the book was inspired by a backpacking visit to Egypt in 1995 and Mr Petre described it as being reminiscent of the adventures of Indiana Jones.

Luigi Bonomi, of literary agents LBA Associates in London, spotted the book among the hundreds of manuscripts he receives each week and said he was “bowled over” by it.

“As soon as I picked it up, I thought, this is really good. It needed a bit of work, but not much.

“The phones haven't stopped and I've got film companies ringing me up as well as US publishers. He's going to make a lot of money.”

Wayne Brookes, senior commissioning editor at HarperCollins, bought the book just a day after receiving the manuscript from Mr Bonomi.

Last night he hailed Mr Petre as “the king of pace”, saying it was the best he had read of this type of book in a long time.

“The key to this particular type of novel, which is very big at the moment, is it's historical, you fell you are learning a lot.

“I thought, this guy really know his stuff. He's taken his time to get it right and it shows.

“The pace is fantastic and that's another key thing. It has to be pacey, people need to turn the pages and come back for more.

Mr Brookes added: “It's also very filmic. I wouldn't be surprised if the film rights went very quickly.

“It's so nice that it's happened to someone who was about to give up. I am really pleased for him.”

It is expected that The Alexander Cipher will be published in November 2008.