Classic tales get a whole new look in two productions opening around town this week. `Move over Moriarty' is a comic reworking of the Holmes and Watson partnership, while Richard III finds himself relocated to an East End pub

How do you adapt a classic? "It's a lemon tree, my dear Watson." (Well, you know what they say, the old ones are the old ones.)

You won't find any such lame wisecracks in Move over Moriarty, the latest literary smash'n'grab from the larcenous Lip Service. After Withering Looks, their oh-so-sensitive, sublimely silly and screamingly funny hommage to the Bronte Sisters, our intrepid heroines have donned literature's most famous deerstalker. Their latest escape finds Holmes and his little friend Watson involved in music-hall murders, and will reveal hidden depths in Death Defying Dan and his whelk-infested Tank of Terror, not to mention Vesta Curry and her Novelty Pipe-Smoking Act.

Some years ago, Lip Service went Shakespearean with Margaret I Parts 2 & 3, a two-person epic inspired by our former leaderene. Of course, they were not the first to take liberties with the Bard. Think of all the musicals. Rodgers and Hart turned The Comedy of Errors into The Boys from Syracuse and then a trio who shall remain nameless did it again last year (with conspicuously less success) under the frankly foolhardy title, Oh, Brother!

As far as I know, nobody has sought to musicalise Richard III (I dare you...), but there was a deeply unmemorable attempt midway through the (mercifully) shortlived The Goodbye Girl. Indeed, long before Ian McKellen made his riveting film version (from Richard Eyre's original staging), the play was already a favourite for inventive production. David Edgar used it as a model for Dick Deterred about Nixon and Watergate, and Olivier made an international name for himself as the hunchback we love to hate with his own classic film version of the original.

The latest adaptation is the brainchild of Eddie Marsan, winner of this column's Most Promising Newcomer award for his knockout performances in The Homecoming and Chips with Everything at the National last year. I'm not alone. As Lindsay Duncan, no less, told me, "He's the real thing."

Having worked with an actor from Northern Broadsides, the company which does Shakespeare in northern dialect, Marsan tried out the famous opening "Now is the winter of our discontent" in broad cockney. Excited by the energy it gave the lines, he, Guy Retallack and Ruth Platt set about cutting the script down to two hours for a "chamber version" set in an East End pub in 1968. He sees his version as a distillation. No major characters have been removed, but roles have been elided for a smaller company. You will look in vain for literal characterisations of, say, the Krays, but the parallels with decadent upper-class characters like Lord Boothby or Christine Keeler are undeniaby there. "That world was very feudal," explains Marsan. "They all achieved power through violence. It's a morality play."

`Move over Moriarty' is at the Purcell Room, South Bank Centre (0171- 960 4242) Wed/Thur. `Richard III' is at The Pleasance N1 (0171-609 1800) from Mon