Tonks’s great contribution to British fish lovers has been the creation of Fish Works: bright, clean fish shops with restaurants attached. These initially spread very successfully across southern England but the past couple of years has not been kind to Fish Works, its investors or Tonks; indeed, what happened could be seen as a classic case of how not to expand a distinctive business. Tonks says: 'I took a battering that left me pretty weary.'

Yet despite this setback, Tonks has bounced back with customary vigour and created a gem of a restaurant. Its location is a great asset, tucked away on the front of this still elegant town facing the River Dart so that every time the front door opens there is a strong blast of sea air. Crucially for a fish chef, the restaurant is only a few miles from Brixham, Britain’s biggest commercial fishing port. Brixham is also Tonks’s home and he commutes every morning by sail boat, sleeping on board whenever the dinner service in Dartmouth finishes too late.

Tonks has created a room that will make everyone feel comfortable. In the open kitchen, Tonks shows off his new toy, a large grill/oven made by Josper in Barcelona. “I initially wanted a wood-burning oven,” Tonks explains, 'but there were too many difficulties with the planners and in the end this has proved far superior. The bars glow white hot and then when you close the door it roasts the fish at the same time. It’s a wonderful way to cook the Brixham red mullet, a fish that’s just coming into season.'

The Seahorse is a family affair with Tonks, his wife, his two partners and their wives, all working there, which seems to add to the charm of the place. Dartmouth itself provides the crab meat served with mayonnaise as well as the lobsters that were delivered as I was eating there. The local squid, served in its own black ink, has a rich, creamy flavour as do the clams, mussels and prawns served with spaghetti, one of Tonks’s personal favourites. Then there are Brixham soles; scallops from Lyme Bay; and whiting, fried and served with chips and tartare sauce, from nearby Torbay. Such local emphasis has obviously worked with Dartmouth’s residents who have constituted most of The Seahorse’s customers since it opened on April 11. Tonks says: 'We need to take £6,400 a week to break even and we’ve been beating that comfortably, I’m pleased to say.'

Tonks remains a director of Fish Works, a company that originated in his first shop in Bath at a cost of £7,500 and grew at one stage to have a market capitalisation of more than £12m on AIM (the London Stock Exchange’s junior market) before its share price fell from a high of 38p to 6p. With hindsight, he saw the cause of its downfall. 'We raised a lot of money but based our future earnings on the opening of new sites. However, once these failed to open on time, something that’s actually quite common with restaurants, we simply could not meet our profit forecasts and we had to issue a first and then a second profits warning. We paid the price.'

New investors and new management stepped in and the first of the new Fish Works has opened in London’s Swallow Street off Piccadilly.

This whole experience seems to have taken its toll and has left Tonks somewhat more subdued than I remembered him. But, happily, he is no less excited about cooking fish. Before I set off he tells me about his next fish restaurant, which will rise out of the redevelopment of Brixham harbour in 2010. 'It’s going to be fantastic', he says, 'because it will be based on what I’ve seen in Australia where the fishermen share in the profitability of what the restaurant actually sells. After all, they’re really the ones who do all the hard work.'

What's on the Menu? Fish and seafood landed at nearby Brixham, along with locally reared meats, cooked over a wood-burning grill. Specialities include seafood risotto and spaghetti with clams.

Can you see the sea? Three alfresco tables on the quayside have views across the River Dart.

How's the mood? Smart waiters and modern decor create a sense of occasion, but the vibe is informal.

What's the damage? Starters from £7, mains £12

I was thinking about this last week as I settled down for lunch at my old friend Mitch Tonks’ new restaurant in Dartmouth, Devon.

Born and raised in Weston-super-Mare, Mitch made his name as the founder of the FishWorks chain of restaurants and fishmongers, as well as through his books and TV appearances.

Although Mitch is still a director of FishWorks, he has recently stepped back from the day-to-day running of the business to concentrate on a new restaurant of his own with old school friend (and fellow Weston boy) Mark Ely and chef Matt Prowse.

Overlooking the river Dart, The Seahorse is an exciting new project for Mitch, mainly because it’s family-run and entirely separate from FishWorks.

The other main difference is that he is back in the kitchen for the first time in six years and he’s clearly loving every minute of it.

Knowing Mitch as I do, I half expected to turn up for lunch to find him sitting in the restaurant with a glass of grappa in one hand and his mobile in the other.

I couldn’t have been more wrong. When I arrived, he was head-down in the kitchen, preparing the fish that had just arrived straight from Brixham fish market.

OK, there was a glass of chilled Prosecco close at hand (well, it gets hot in the kitchen), but this was the Mitch of old - before his days were spent in dull meetings discussing targets and business strategies.

The Seahorse is a charming restaurant with a timeless quality. It feels like it’s been there for decades. It’s only 40 covers and Mitch and Matt are cooking every day in the open kitchen.

The food is inspired by Mitch’s travels, particularly in Italy and Spain, and it’s matched with a brilliant wine list.

Even though he’s a friend, I can still honestly say that my lunch was as good as any I’ve had this year.

Highlights included chicken livers wrapped in wild garlic and sage and roasted in the wood-burning oven; homemade gnocchi with braised veal shin, beef and porcini, and a faultless Dover sole meuniere.

I visited The Seahorse on only its fifth day of business, but the word had clearly got out that Mitch was back in the kitchen as there were already people from Bristol and Clevedon in the restaurant.

A celebrity chef back in the kitchen and cooking for paying customers? Whatever next?

With backing from partners Mat Prowse, another well-known chef, and old friend and professional South Hams musician Mark Eli, the Seahorse opens its doors for the first time on Friday.

Mitch said: "We're booked solid already with just a few places in the middle of next week.

"I'm delighted with the boat, which has been built in Turkey.

"It's a five-metre Classy 17, and will allow our guests to really linger over their courses without having to sprint off to get the public ferry to Kingswear.

"Our speciality is going to be the freshest local fish and that's what our diners are already asking about and of course local suppliers of top quality meat and vegetables."

The award-winning restaurateur will be operating just two doors away from the New New Angel but says there's no rivalry with its manager, TV personality John Burton Race.

Mitch, Mat and Mark have already installed a Continental wood-burning grill and all the cooking action can be watched through a large window at the rear of the 45-seater dining area.

Dishes will include a starter of Dartmouth crab, dressed to order, a plate of local fried seafood, a cutlet of English veal with anchovy and parsley or chicken livers wrapped in sage and grilled over wood-burning fires.

Brixham-based Mitch, best known for his links with the national Fishworks empire of shops and eateries, says the Seahorse will also celebrate seasonality from regional markets: olive and rape seed oils, South West cheeses, fruits and vegetables and local cured meats.

The Fishworks chain of eaterie-fishmonger-chef school started 10 years ago in Bath. It has expanded to Bristol, Christchurch and London, where the Chiswick and Marylebone centres have already won ITV's top UK fish restaurant titles.

All the centres feature in the Which? Good Food Guide.

Mitch said: "The Seahorse is inspired by travels around Italy and Spain where dining out is an everyday, simple experience with great food served in a relaxed but informative manner.

"Going back to running a local restaurant is something I can't wait to do.

"Being fully involved from knocking down walls to creating the menu and sourcing local produce is all part of creating what we believe will really inspire people to come and visit us," he said.