Roland Emmerich's forthcoming film Anonymous propels the director of Independence Day and The Day After Tomorrow into a brave new world, 16th and 17th century England. As Prospero said to Miranda in one of Shakespeare's most famous lines, "Tis new to thee". For the rest of us, it is just a return to the blasted heath of the authorship question.

Anonymous is not released until the autumn, but already we know from advance publicity that Emmerich's film adopts the Earl of Oxford's claims to the plays lock, stock and smoking muskets.

The devotees of the belief that Edward de Vere is the real author of the canon, despite his inconveniently early death in 1604 (ie before the first productions of Macbeth, King Lear, Coriolanus, The Winter's Tale and The Tempest), derive a good deal of their confidence from the advocacy of Sigmund Freud. This fantasy turns the plays into the surrogate autobiography of a secretive literary earl.

I have no idea how faithful Emmerich is to this line of argument, which is supported by Derek Jacobi and Mark Rylance, but it's interesting that the director chose to ignore the almost equally far-fetched, but far more melodramatic, authorship plot that's based on the strange and violent death of Christopher Marlowe.

To the hierophants of the Marlowe Society, the playwright was not murdered in a Deptford tavern after a row about the bill ("the reckoning"), but spirited away to France through court connections (Marlowe was a spy). There, for the next 20-odd years, he wrote the plays attributed to Shakespeare, smuggling them back to London through diplomatic channels.

I suspect that Emmerich did not adopt this scenario because it has already been wittily spoofed in Tom Stoppard's Oscar winning Shakespeare in Love. However, the Oxford scenario, which has never been filmed, is virgin territory.

Either way, Emmerich will only now begin to understand what he's let himself in for. The internet is the natural home for conspiracy theories, and the Oxford case is a conspiracy theory in doublet and hose with a vengeance. Anonymous may be good, bad, or indifferent: but it's going to mean open season for every denomination of literary fanatic. To glimpse what this can involve, just open any page of James Shapiro's Contested Will, Who Wrote Shakespeare? a scholarly account of the leading anti-Stratfordian theories.

It remains to be seen if this is box office (Shakespeare in Love certainly was). One thing is certain: Anonymous is going to generate a lot of column inches. Since all publicity is good publicity, it may even have the unintended consequence of introducing a new author to the canon, albeit under a wholly false prospectus.