The next time the Pope addresses crowds in St Peter's Square, he may see tourists with paperbacks by the blockbuster conspiracy novelist Dan Brown, rather than Catholic pilgrims with Bibles or guidebooks.

The first "official Angels and Demons tour", organised by a group of thirtysomething Romans specialising in the "darker side of Rome", will show visitors the Roman sites used by the author of The Da Vinci Code.

Da Vinci Code spawns tourist trade continued