Laurence Gardner's first book Bloodline of the Holy Grail was published in 1996. The book was serialized in the Daily Mail and a best seller. He used his books to propose several theories, including a belief that Jesus and Mary Magdalene had married and had children, who's descendants included King Arthur and the House Of Stuart. In Lost Secrets of the Sacred Ark he claimed that the Ark of the Covenant was a machine for manufacturing "monatomic gold" - a supposed elixir which could be used to extend life. His books also included theories about Freemasonry, the Knights Templar, The Holy Grail and proposed connections between Atenism and Judaism.

Gardner described himself as "Chevalier Labhran de Saint Germain", and "Presidential Attache to the European Council of Princes" also "Prior of the Celtic Churches Sacred Kindred of Saint Columbia". Entropic Fine Art Inc - Book He also claimed to be Jacobite Historiographer Royal of the Royal House of Stewart. He was a supporter of Michael Lafosse, in particular his claims to be descended from the House of Stuart, which Gardner claimed was descended from Jesus Christ.

Historians and scholars regard him as a conspiracy theorist, and treat his work as pseudohistory. Michel Lafosse's claims have been dismissed.

Laurence Gardner was also known in the United States for his radio phone-ins.

It was announced on his personal website that he had died on 12 August 2010 after a prolonged illness.

Gardner was born in Hackney, London, he was married to Angela and they had one child together and two children from a previous marriage. He was a stockbroker before taking up writing. Gardner was also an accomplished painter, working alone and with Canadian artist Peter Robson.