John Wilmot, Earl of Rochester, was the embodiment of the swinging '60s. The 1660s, that is, of Restoration England. In his entertaining opening address, Wilmot, played by Dominic Cooper, wants to make two things clear. The first is for all the ladies in the audience. "I'm up for it," he declares. The second is for everyone. "Do not like me," orders this misanthropist. Though who ever heard of a literary, self-destructive, sexually rampant dissolute who was unlikable?

Stephen Jeffreys' 1994 play - later made into a movie starring Johnny Depp - was first seen when staged as a companion piece to George Etherege's work about Wilmot, The Man of Mode, written while the notorious Earl was still gorging himself on the freedoms that followed Cromwell's puritanical rule. And, in many ways, Jeffreys version is more convincing than Etherege's, making few concessions to decency, a virtue that Wilmot abhorred. More dangerously, the Earl despised monarchy as exemplified by Charles II (a terrifically in-form Jasper Britton). Though the rake is a serial offender against courtly etiquette, Charles nevertheless recognises his literary talent and commissions a play for the newly reopened theatres. The work is to be a monument to Charles's reign, and so it is, though a stage full of phallus-waving wenches might not have been the monument that the king had in mind.

Yet for a play that in part celebrates the sport of extreme living, Terry Johnson's underpowered production fails to drum up more than passing interest. The same could be said for Cooper.

It is the screen star's first stage role for seven years and he plays it with such an even temperament that any interest in the fate of his Wilmot eventually evaporates into the urine-coloured haze in which designer Tim Shortall's artful vision of drunken London is lit.

There's much to be said for underplaying a role, but Cooper never unleashes the required performance. His Wilmot is not so much depraved, as rather naughty. And there is little sense of danger brought to a character who in theory holds no fear of authority, God or death. Only Britton's sarcastic, self-parodying Charles II injects life into this eventually insipid evening. As for Cooper's Earl, from me he elicits the response that Wilmot least wanted. I rather liked him.