The restaurant opened a couple of weeks ago in what used to be Hanrahan's bar, becoming the first of the Scottish seafood chain to take over a former pub site.

"The brewery saw profits slide because of the smoking ban, so they've teamed up with Loch Fyne to turn some of their premises into restaurants," explains deputy manager John Allsop. "It seems to be going down well – lots of people have said this is just what Sheffield needs."

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It certainly makes a change from the all-too-common fried food and beer offer presented by so many chains.

Loch Fyne started life 20 years ago as an oyster farm in the Scottish lowlands.

These days it is a fast-expanding, up-market group specialising in ethically-sourced seafood: "We do not source fish from deep sea trawlers. We do not fish endangered stocks," it boasts.

Oysters, naturally, are on the menu, along with shellfish platters, smoked salmon and a whole range of other seafood treats – and token steak, sausages or lentil casserole for non-fish eaters.

Loch Fyne does breakfast too, so aficionados can call in on their way to work for smoked kippers, haddock and poached egg, or even a full English.

The wine list is extensive, big enough, in fact, to wrap up a decent-sized portion of fish and chips in. It's user-friendly too, with wines listed according to their attributes. Choose between 'floral and zesty' viognier (£16), 'rich and luscious' chablis (£28) or 'vibrant and fruity' Cotes du Rhone (£21); glasses from £3.50.

Hanrahan's was something of a Sheffield institution in its day and efforts to update it over the years have met with mixed success. The latest incarnation finds a niche of its own.

The place is bright and airy, mainly magnolia, with polished wood tables left bare. Driftwood sculptures, Scottish landscapes and pithy gaelic quotes add interest but the focal point is undoubtedly the fish counter.

Replacing half of the old bar area, this is decked out like an old-fashioned fishmonger's with chequer-tiled wall, marble cabinet and a mind-boggling array of sea creatures arranged on a bed of crushed ice.

And it's not just for show – the restaurant doubles as a fresh fish shop where customers can buy dinner and cook it themselves at home.

We're more than happy to leave the cooking to head chef Jaroslav Varga and his team, so we take a table in the restaurant area.

Service is good and waiter Charlie brings us a basket of bread (fresh but not home-baked), glasses of house red ('soft and smooth' merlot grenache) and a big jug of iced water.

My companion starts with smoked haddock chowder, creamy and filling with chunks of fish and potato.

It's "fab" – but probably not the best choice for the slender type who is generally full after one course – especially as she has promised to make an effort for the purposes of research.

I'm not an oyster fan (delicacies they may be but they still taste like seawater to me and I can't see the point of swallowing food without chewing it). However, I do have a penchant for scallops, which are on the specials menu.

They're grilled with garlicky butter and served in a six-dimpled dish – one dip for each nugget of sweet, succulent scallop. But they're half the size of the meaty, hand-dived variety and at £1 each they're not cheap.

On to main courses and my skinny chum goes for the most filling dish on the menu, fish pie with cheddar gratin. The lovely Charlie tries to warn her off but her mind is made up. And the warning proves unnecessary: she wolfs down the lot – salmon, haddock, sauce and even the cheesy potato topping.

I go for bradan rost (it's Gaelic for roast salmon). "Ah, lovely, luscious braden rost," sighs Charlie in his broad Scots brogue. And he's not wrong.

The fish is traditionally soaked in brine and brown sugar, then chargrilled, emerging crisp-skinned and delicately flavoured (the strong-smoked version is bradan orach). It's complemented by a mushroom and whisky sauce, garnished with shell-on cockles and mussels.

The only black mark is the 'seasonal' veg – a choice of broccoli or peas (neither of which is in season) at £2.50. And another £2.50 if you want potatoes too.

I decide to do without the spuds but £2.50 for a dish of frozen peas is enough to leave a bad taste in anyone's mouth, especially on top of a main course that has already cost £13.

My companion, valiantly attempting to keep her promise, then manages to polish off a slice of fudgy chocolate and orange tart, creamy and rich on a biscuit crumb base, with a tangy pineapple and ginger compote – a great combination.

I have the 'ashet' of fruit, which turns out to be Scots-franglais for an assiette of melon, kiwi, pineapple, grapes, mango and strawberry.

We finish with decent coffee. Dinner for two, excluding wine and service, is £51.

Verdict: For fish fans, Loch Fyne will surely live up to its name; veggies would be well advised to look elsewhere.

Open: daily, 9am until late

Loch Fyne, Glossop Road, Sheffield (0114) 270 3940

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