Dumb Show by Joe Penhall, directed by Peter Evans. With Aaron Blabey, Anita Hegh and Richard Piper. Designed by Christina Smith, lighting design Matt Scott, music by Darrin Verhagen. Melbourne Theatre Company @ the Fairfax, Victorian Arts Centre, until February 18.

Joe Penhall is that very British phenomenon, the straight-talking celeb. Asked what he thought the problems of British theatre were, he responded: "Too much mediocrity in the West End. It's like watching BBC1. They're just milking the tits of a giant, wobbling, quivering fucking middle-brow cash cow if you ask me."

Ironically enough, without the profanity (I am a courteous and restrained individual) that was more or less my sentiment at the end of Penhall's Dumb Show, a play about the mutual parasitic relationship between celebrity and tabloid journalism. It's a classic issue-based play, setting up a confrontation with enough moral ambivalence to keep the audience teetering to and fro in their sympathies, without reaching so far into the heart of things that it confronts anything too visceral. Middle-brow indeed.

My first, not very interesting, thought about Dumb Show was to wonder why a story about the grubby hypocrisy of British tabloid newspaper journalists would be of interest to Melbourne theatre goers. Australian tabloids have got nothing on the excesses of Fleet Street, nor can we match the trashy glitz of British celebrity; and the issues as presented here have little to do with us. But then, I will follow with breathless interest stories about decaying 19th century Russian bourgeoisie or 12th century English kings, without the question of irrelevance entering my head. The real question is, I think, one of sentimentality.

In Dumb Show, Richard Piper plays Barry, a vain and insecure tv celebrity. He becomes the target for entrapment by a pair of unscrupulous tabloid journalists, Greg (Aaron Blabey) and Liz (Anita Hegh), who disguise themselves as bankers and dangle the bait of a huge fee for a dinner talk. Of course, behind the moral outrage of the journalists lies the grubby business of the scoop, the voyeuristic and predatory amorality that feeds on the pain and humiliation of its former favourites. But, as the play reveals, it is a symbiotic relationship: the celebrity needs the press as much as it needs him, to feed his fame and his egotism.

And that, really, is as far as it goes.

I have heard sentimentality described as "unearned feeling", and it's a description that fits this play to a tee. I have seldom seen a work so brazenly manipulative, shamelessly raising the emotional stakes to wring the hearts of the audience, without anywhere risking real feeling. And of course it's full of jokes, defusing moral or emotional discomfort with those crackling one-liners. Yes, I laughed at one or two of the jokes, but less and less as the show went on.

In this, I fear, I was a little solitary: the MTC audience lapped it up, practically booing the villains and cheering the main guy as if it was a Victorian melodrama. I sat, as Michael Billington once memorably said, in "mutinous isolation". I don't like having my feelings pushed around, as if my mind is nothing but a series of buttons to be pressed by this or that turn of the plot: if I want that, I can always watch Neighbours.

It's a shame to see such a talented cast and director spending their efforts on work so unrewarding. Anita Hegh, in particular, was unable to access her considerable powers in the character of Liz, who is, like her colleague Greg, thinly drawn; neither of the journalists are much more than empty representations of the moral and emotional bankruptcy of their profession. Richard Piper as Barry, predictably, makes a meal of his role, which gives him plenty of scope: his character is pathetic, greedy, morally dubious, vacuous: but also raffishly charming and funny. His performance, like all the others, has that painful sense of actors mugging their roles, going for crude surface in the absence of any other ideas. But, given the script, it's hard to see what else they could have done.

Peter Evans' direction is competent, ensuring the show runs smooth and fast. At the beginning, he has the two journalists enacting their roles-within-roles as heightened, almost grotesque caricature, dropping this style when they reveal their "real" selves. It's an interesting idea that doesn't come off, partly because then it's difficult to see how Barry could possibly have been taken in by them.

In short, another play that slips out the memory as soon as you slip out of the theatre: slight in every respect, vaguely insulting in its manipulativeness, curiously untouching. The kind of thing, the MTC would argue - with some justification - that it is forced to do in order to keep the box office ticking over: as one might say, "milking the tits of a middle-brow cash cow". But that's another argument.