Goodfellas is in Kennedy Way, just off the Falls Road, a Catholic-owned joint on the edge of a loyalist enclave strong on militant murals, marching and, not so long ago, rifle-volley shows of strength. The windows are smoked dark and impenetrable. The patch of grass outside is littered with empty bottles of WKD Blue. Two sets of entry doors, of which the outer one was formerly remote-controlled, testifying to times when the threat of a loyalist "spraying" was very real. Times when the least of your worries was a dodgy restaurant review. Gordon Ramsay at Claridge's this most certainly ain't.

It is about three-quarters full inside, which is impressive on a wet week-night in March, and almost everyone is fat. Obesity in West Belfast seems to be even worse than in the poorest areas of mainland Britain. There is what appears to be a hen party in the next room comprising 12 women seated around a large square table, each of whom, on her own, weighs as much as a whole hen night of women from Fulham. (I guess these are battery hens).
The men have big square heads and little pink faces, short spiky hair, stud earrings and big appetites. It's like Westlife got old and fat overnight, which they sort of have if you saw them on Al Murray the other night.

To be fair, the welcome is not, as The Irish News had it, "daunting" or negligent. A very pretty and charming waitress seats me at a very small table next to some very large people. She brings me a glass of cola (Goodfellas has no licence) which is, indeed, pretty flat and not especially cold and (as The Irish News critic claimed) clearly not poured from a bottle but shot from a gun. So much for decommissioning.

The menu is terrifying. Hundreds of choices – 14 starters, 14 chicken dishes, 15 pizzas (including "The Whop"), 13 pasta dishes as well as a do-it-yourself option, where six styles of pasta can be paired with a cream or tomato sauce and any permutation of 25 further ingredients to create millions of possibilities (if you've ever fancied rigatoni with smoked salmon, sweet-corn and barbecue sauce, Goodfellas is the place to get it).

Then there are ten beef dishes with ten sauce options (100 more possible combos there) including the alluring-sounding "gravy". Half a dozen pig dishes, some specials and 24 contorni (this is an Italian restaurant, don't forget) of which eight are potato.

Portions are massive. Waitresses struggle by with Brobdingnagian tureens of pasta and pizzas like dustbin lids (but smellier). I order a small far-falle all' arrabiata, and then the chicken marsala – the very dish that Caroline Workman, the Irish News critic, had described as being served in a sauce so revoltingly sweet as to render the dish inedible. I nip to the loo. Two of the cubicle doors are locked but the third opens, straight into the kitchen. Most unusual. This does not happen at Le Gavroche. Perhaps I am spoilt.

My little pasta dish arrives. A huge disappointment: it is fine. Not fine in the sense of tasting like something an Italian would dream of eating. But fine in the sense of being the sort of thing I used to cook as a student when I was too stoned to dial a pizza.

The chips I ordered are fine, too. Precut and frozen, yes, but that's normal even in a good gastropub, and these are nice and crispy. I am gutted. It looks like there will be no opportunity to test my rejuvenated confidence in a restaurant critic's right to freedom of expression.

Then my pollo marsala arrives: an oval dish containing a chocolate coloured liquid and pale lumps of something. I eat a mouthful. The sweetness is, indeed, alarming. As is the consistency of the meat. Without the court papers to confirm what I had ordered, I'd have guessed I was eating thin strips of mole poached in Ovaltine.

It is revolting. It is ill-conceived, incompetent, indescribably awful. A dish so cruel I weep not only for the animal that died to make it, but also for the mushrooms. Ms Workman said it was inedible but, to be honest, as it sits before me, congealing quietly, I cannot leave it alone but return to it every few minutes with the grim fascination of a toddler mesmerised by a pile of its own faeces, nibbling at it, gurning with revulsion, then nibbling some more. If you've ever sniffed your finger after scratching your arse, and then done it again, then this dish may not be entirely wasted on you.

A note on the menu says: "All of our meals are freshly prepared." When I ask for parmesan cheese, they bring a pot of that powdery pregrated grit that smells like dessicated dog vomit. I thought I'd better have a pudding, so I ordered the apple crumble. Alas, what they brought me resembled a mixture of budget muesli and aquarium gravel served in an old man's slipper. The accompanying custard was pleasant only in that it reminded me of a scented pencil eraser I used to enjoy sucking in the hot summer of 1976.