I Am Shakespeare: Mark Rylance, Arts Theatre, Cambridge

I Am Shakespeare: Mark Rylance, Arts Theatre, Cambridge

My schoolteacher told us that if Francis Bacon wrote Hamlet, King Lear and the rest then an English breakfast would probably be known as Shakespeare and Eggs. Perhaps only English teachers and others with an obsessive interest - such as a former artistic director of the Globe Theatre - are really concerned with the authorship of the plays.

That Mark Rylance, who ran the Globe Theatre for ten years, should write, co-direct and star in such a screwball comedy as I Am Shakespeare, almost suggests a measure of embarrassment at his own professed position as a Stratford doubter, or at least a fence sitter.

Once you start wondering whether a humble actor from Stratford-on-Avon would have as vast a knowledge of as many subjects as Shakespeare's plays demonstrate, you're off down Conspiracy Theory Avenue.

Rylance himself plays a literary geek, Frank Charlton, rejected by academia, and now reduced to webcam chat-room broadcasting his opinions from his garage. His show, called 'Who's There?', has an 0845 number for the non-existent callers. He's an anti-Stratfordian, believing that anyone but Shakespeare wrote the plays.

Then, in full Elizabethan gear, Shakespeare (Colin Hurley - a real Bard look-alike), Bacon (Roddy Maud-Roxby), the Earl of Oxford (Alex Hassell) and later Mary Sidney (played by Mark Rylance's step-daughter Juliet) turn up at his garage studio to argue their own personal cases. They row and fight so loudly that the local copper arrives to see who's disturbing the peace. Within minutes, he's making parallels with the endless theorising about the Jack the Ripper murders.

It's all frenetically crackpot. Shakespeare's a bit of a drinker. 'Exit, pursued by a beer,' he says, after raiding Frank's fridge.

Then there are the audience participation moments. We're asked to vote for whom we think wrote the plays. We're also lured, as in the film Spartacus, to join with the actors as each puts up a hand and shouts 'I Am Shakespeare'.

The action is further complicated by it being videoed by Rylance or his neighbour pal Barry (Colin Foley) so that we can watch it on two screens.

It's a fine vehicle for Mark Rylance's exceptional comic talents. In a flash, he changes from an earnest normality to a mania that convinces us that Frank is completely bonkers.

And yet earlier this month Rylance and Sir Derek Jacobi unveiled what they described as a 'Declaration of Reasonable Doubt' on the authorship of Shakespeare's works. Underneath then, this comedy isn't joking.

Ivan Howlett