A waiter approaches our table at the slouch. "Veal?" he asks. Then he shouts it. "Veal!". Stewart looks up. "I'd love to, thank you". Waiter glares at him, slams his plate down and departs. "I don't think it's that sort of restaurant, darling," I say. "It never is," says Stewart.

The support man is covering the Lighthouse Family's "Lifted" and the crowd is going wild. Ever since that car ad, the Lighthouse Family have had a rapid, if profitable, descent into the realm of the easy listening classic, and now 100 girlies with frizzy perms are swaying over their escalopes and going "Wikkanbi lifted, from the shad-o-oze, lifted, leaf- te-e-ed".

The anticipation mounts. Every now and then a female voice shrieks above the music: "Elvis! Where's Elvis!". The support guy does "Sexual Healing" and for some reason the men scattered around the room in their Adidas T-shirts cheer up and start to sing too. I haven't been in such an unadulteratedly heterosexual atmosphere since Bob Dylan played Blackbushe back in '76. Which is odd, because the disco between sets seems to consist almost entirely of the sort of music they used to play in gay clubs in the Eighties. The place is staffed by angry Italians with terrific backsides, who slam the menus down and stalk off with haughty disdain. Maybe they despise us for trying to eat the food they've obviously been spitting in, but I think it's probably just that Saturday nights are a bit of a strain.

The support guy's synth bursts into paroxysms of rising chords, the speakers juddering with the effort of keeping up. The restaurant lights dip, rise, dip again. The King is coming. A ripple of applause and a crescendo of howls from the front door, and he is among us in his white sequinned Vegas catsuit and his crow-feather black quiff: Elvis Presley, back from the dead. He jogs up the aisle between tables, shaking a hand here, doling out a high five there, somehow reaches the stage in one piece, curls his lip, shakes his right leg and launches into "Hound Dog".

The dance floor, empty a few seconds ago, is immediately heaving with hens. There are two hen parties in tonight, each containing about 20 people. One lot are dressed like schoolgirls in plaits, gym slips and face paints. The others are a bit more sedate, and arranged according to age: shoulder- length perms, miniskirts and bare legs at one end of the table segueing through to blonde shower-cap hairstyles, silk-look polyester blouses and square, clear-framed specs at the other. At this table you can watch the full life-cycle of Suburban Woman in the course of seconds. "There'll be chicken a la King at that wedding," says Paul, as he toys with his cheesecake.

Every time Elvis jiggles his leg, more screams echo from the crowd. The schoolgirls who haven't made it to the floor line up on top of their table and do a dance routine: left arm, right arm, left leg, right leg. The cross waiters tell them to get off and hand them down at arm's length, as though they're spiders. A birthday cake floats past, candles burning, carried by someone who looks suspiciously like Harvey Fierstein in Torch Song Trilogy but actually turns out to be a bona fide woman with an Adidas T-shirt in tow.

Down on the stage, things are getting a bit hot for the King. Hen parties being what they are, everyone wants to be up there with him. A bride is lifted bodily up to be serenaded and looks all shy-but-radiant, like brides are supposed to. Elvis lets her go, starts singing "Walk like an Angel", and then one of the bride's friends leaps in for a try. She must be 60, with cropped blonde hair and surprised eyebrows, and she cuddles up to him, with one of those butter-wouldn't-melt expressions. Elvis cuddles her back, and suddenly his voice leaps an octave. She's stuck her hand down the front of his trousers. He fights her off, still singing, while her girlfriends bay their approval from down below. She tries again, and Elvis gets the giggles. They're nothing if not tenacious in Streatham.

"Blue Suede Shoes", and three hens line up in a row with their arms round each other. A 10-year-old girl gets up and simply stands there, looking embarrassed in a lycra crop-top and white socks. Elvis changes into a red catsuit, comes back and sings "The Battle Hymn of the Republic", full vibrato, then wades into the audience to hand out birthday wishes. Sings "The Wonder of You" and poses for photos, snatching the odd snog off the birthday girls. I can't resist. "Elvis!" I shout, "Over here!" He advances, smiling. I point at Jonathan, who's looking at me like thunder. "It's his birthday, too!" I shout. "Uh-uh," says Elvis into his mike, "Not me, man". He shakes Johnny formally by the hand and hurries away to do his duty among the breeders.