Like Crisco or Regis Philbin, Palm is one of those great American institutions to which the rest of the world is oblivious. The granddaddy of New York steakhouses, it has grown from a family-run restaurant, founded in Manhattan in 1926, into a 27-strong chain. In the States, Palm calls itself the original "place to see and be seen". Over here, it's the place you haven't really heard of.

Unless you're an American expat, that is, homesick for filet mignon, broiled crab cakes and grilled shrimp salad. In those circles, there has apparently been rejoicing at the arrival of Palm, on a Belgravia shopping strip which couldn't be more uptown if Christie Brinkley was high-stepping outside with a bunch of motor mechanics.

No tables were available for a Saturday night dinner, apart from at 6.30pm. And who on earth eats out at 6.30? (Oh yes, that's right, Americans...) So we booked in for an early Saturday lunch, having first been assured by the reservationist that the place was child-friendly.

What she didn't tell us was that Palm is child-friendly, even for adults. The walls are covered with cartoons, celebrity caricatures (including – yes! – Regis Philbin) and framed memorabilia, copied from the Manhattan original. This startling design feature apart, the look is standard steakhouse – dark woodwork, booths, and a bar lined with high stools – recreated in shiny new materials.

The staff, some of them brought over from the States for the launch, are the real deal. From the moment we arrived, we were engulfed in a blitzkrieg of efficient charm. Our waiter Michael, on loan from the Orlando branch, rapidly became our new best friend, addressing the kids as "buddy" while guiding us through the Palm way of doing things. It could have been annoying, but it was done with such genuine friendliness, we began to feel he actually loved us. "This is great – just like being in America!" Harry marvelled.

Then the food arrived. First, a basket of slightly dried-out raisin and hazelnut bread. Then, with a tableside bustle involving several waiters and a bus boy, the starters. Can this really be the food on which an empire was built? Fried calamari – a hangover from the original Palm's Italian menu – were light and crisp, but piled on a pointless bed of iceberg lettuce, and served with a revoltingly sweet tomato dip reminiscent of a cook-in pasta sauce.

Shrimp Bruno, another Palm signature dish, doesn't, alas, fly through the air and park its bare bottom in your face. Instead, three butterflied and lightly battered shrimp (or as we would call them, prawns) sit forlornly in a white wine and Dijon mustard sauce which again struck us as unpalatably sweet.

We took our new buddy's advice "to get a little surf and turf thing going" and paired one of the fabled New York sirloin steaks, made with imported USDA prime beef, with a 2lb lobster, flown in twice-weekly, Michael assured us, "from the ice-cold waters of Nova Scotia". There followed an interval during which we could have comfortably surfed over to Nova Scotia and brought back a lobster ourselves. The kids were getting frantic, Michael even more so, darting over repeatedly to tell us our food was on its way.

And then it happened. The cataclysm. Running upstairs from the kitchen with our main courses on a tray, Michael dropped the entire lot. The noise brought the restaurant to a shocked standstill. When, after a tense interval, Michael reappeared at our table, he was a broken man. Profuse apologies gave way to a mock-jaunty monologue: "I'm gonna buy you dessert! Do you guys like Key Lime pie? The juice is flown in specially from Florida. That's where I'm from..." Like a malfunctioning robot, he spieled on, over the sound of sweeping up and china crunching underfoot.

All of which put us under pressure to enjoy our surf and turf platter when it finally arrived. Thank God, the steak was first-rate, smokily charred outside, ruby red inside. The lobster, though, was ... hmm; the claws pre-cracked, the body split and finished under the grill with parsley butter, it had a kind of vacuum-packed quality that called to mind not so much the sound of the sea as the whooshing of the 747 that brought it here.

Michael put the puddings down, with a "Yummy yummy!" that I fear wasn't just for the benefit of the children. "This must be what it's like to live in a care home," Harry whispered. The famous Key Lime pie was good, if you like sickly, creamy puddings; chocolate fondant, however, was too sweet even for our 8-year-old.

True to his word, Michael deducted our puddings from the bill, but it was still hefty; that 14oz steak costs a staggering £49. And that's about the only part of the Palm experience which doesn't feel authentically American; in the States, it's possible to leave a mid-market restaurant without feeling you've been mugged. Michael, we loved you, we'll certainly look you up should we ever find ourselves in Orlando. But with Palm, our special relationship just isn't going to happen.

Palm, 1 Pont Street, London SW1 (020-7201 0710)

Food 3 stars
Ambience 2 stars
Service 4 stars

Around £50 a head. Prix fixe lunch menu £15 per head

Tipping policy: "Service charge is 12.5 per cent discretionary, of which 100 per cent goes to the staff; all tips go to the staff"