Meat Loaf, Wembley Arena, London

As The Darkness walk the ironic-rock tightrope up the charts, spare a thought for the genre's pioneer. Meat Loaf in his prime was uniquely hilarious: the epic rock hero consoling his lover with "I want you / I need you / But there ain't no way I'm ever gonna love you / Now don't be sad / 'Cause two out of three ain't bad".

But the power of this human mountain's voice was such that he could also shiver your timbers, booming out such nonsense seemingly with utter sincerity. You laughed till you cried and then realised you were crying for real.

The problem, then, was the suspicion that the joke wasn't really Meat's but songwriter Jim Steinman's. So tonight it's a relief to see him joking from the outset, stretchered onstage in mockery of the heart condition that forced him to cancel several concerts this year. Later, after the immortal lines "Ain't no doubt about it we were doubly blessed / 'Cause we were barely seventeen and we were barely dressed" in 'Paradise by the Dashboard Light', Meat decides to play 'name that animal'. He lies down on his back and spouts water. "It's a whale!" exclaims the backing singer. "Yeaaaaaaahhhh!" roars the rock'n'roll Loaf, raising his hands in the air to milk the applause as the guitarists head off on another lengthy bout of glam-metal duelling.

None of this would be half as funny, however, if Loaf were not so ridiculous-looking. Though half the man he used to be, he's still decidedly roly-poly. Unsteady on his pins (he actually falls over at one point - worth the ticket price alone), he struts the stage hollering randomly like a toddler in a tantrum. As he strains for the high notes, you feel like chucking him a laxative.

What you're really laughing at is neither his jokes nor the tongue-in-cheek lyrics: it's his unseemliness as a rock star.

And what's sad is not the operatic drama of the songs, but that of Meat's own predicament. When he sings "All revved up" sitting hunched over in a schoolboy's baseball jacket, you realise the joke's still on him: he's just making money out of letting people laugh at the lonely fat weirdo the song describes.

For the real tragedy is that he can't carry the song. Tonight, bellow and wheeze though he might, Meat's singing is dire. The backing vocalists gamely carry most of the melodies. They also put up with the sexist jokes to which Meat resorts in a show that is more pantomime than rock concert. Sides are duly split, but for all the wrong reasons.

As Meat beats his chest in glory at the end, you can't help thinking that some of the audience might have liked to hear him sing "Bat out of Hell" properly.

Meat Loaf plays Sheffield Arena on 15 Jan and Wembley Arena on 22 and 24