Mark Derry is wondering what happened to all those other fish. “It's a funny industry,” he says. “I wouldn't want to sound disparaging, but everything today is line-caught or fresh. As to the stuff that comes off the trawlers, I don't know where that goes.”

Presumably to the manufacturers of ready meals, to emerge in due course as fish cakes or fish fingers. Certainly none finds its way to Loch Fyne, the 40-strong restaurant chain where Mr Derry is chief executive.

The chain was spun out in 1997 from Loch Fyne Oysters, the fresh fish business in Strathclyde on the bank of Scotland's biggest sea loch. This came to unexpected political prominence in 2004 when it was allegedly the site of a meeting between Gordon Brown and John Prescott to stitch up the Blair succession.

At the time Mr Derry said of the so-called “oyster summit”: “You couldn't buy publicity like that for less than about £20 million.”

We meet at the wet fish bar that Loch Fyne opened earlier this year in Wimbledon Village. This is one of the most prosperous areas on the planet, replete with chi-chi fashion boutiques, astronomically priced childrens' clothes shops and organic delicatessens.

Even so, one local blenches at the price of Dover sole, admittedly one of the most expensive on the slab. All of which is line-caught or extremely fresh, of course - never frozen.

The bar is a joint venture between Mr Derry's chain and the now unrelated Loch Fyne Oysters. The latter supplies fish to the restaurants, which have the right to the Loch Fyne name. The produce is sourced almost entirely from Britain, much of it from the loch itself. They have, for example, the rights to almost everything caught by a day boat operated by a father and son outfit from Looe in Cornwall.

Mr Derry's career in catering started at Whitbread, which owned chains such as Café Rouge and TGI Friday's, where he worked for a time, and was a forcing ground for many subsequent entrepreneurs. It progressed in 1997 with the sale of Country Style Inns, which he had acquired for his then employer Glenchewton, which distributed cookware.

He and another former employee, Ian Glyn, teamed up to find a venture in the restaurants field. “Everybody was doing pizzas. We thought, how many pizzas can people eat? There was an issue in steak or meat with BSE.” Prompted by his wife, Sara, and by holiday memories of plates piled high with fruits de mer on the west coast of France, he plumped for fish.

“Ian and I were looking for sites for our own seafood business. Johnny Noble, the founder of Loch Fyne, found out. He phoned us up and said ‘let's do it together'. Ian and I put in a little money - not very much, I think it was fifty grand each.”

The rest came from friends, colleagues and other investors. Many of these, such as Lord Cadogan, were drawn from the contacts book of the eccentric founder, a man for whom few have an unkind word, who died in 2002.

They managed to raise the rest of the £1.4 million needed for the new company, Loch Fyne Restaurants. There were already two restaurants outside Scotland, oddly situated in a rough area in Nottingham and in a small village outside the city. Neither was a conspicuous success. The village site was a converted cowshed, as was the original Loch Fyne restaurant; as to the city site, Mr Derry says, “the thing that struck me when we first looked at it was that it hadn't gone bust”.

The first new outlet was in Cambridge. Further expansion was fast. Too fast. “We were opening restaurants so quickly, hiring managers, putting them in along with new staff and saying, thanks, cheerio, we'll be back next month to pick up the money. It doesn't work like that.”

In 2005 the company announced a strategic review, “which is a euphemism for saying we're up for sale”. Venture capital firms formed an orderly queue and Hutton Collins, run by former bankers, was successful.

At that time the business was worth about £33million. The next year Mr Derry engineered the £3million purchase of Le Petit Blanc, which had its roots with the restaurateur Raymond Blanc but was deemed too small by the venture capitalists, to create his own independent chain, Blanc Brasseries.

Last year, in an unexpected move that did not entirely suit the venture capitalists, Loch Fyne Restaurants was bought by the brewer and pub operator Greene King. This was seen as a defensive move. The smoking ban was threatening the pubs trade and most operators were aware that large swaths of their estate were probably no longer viable.

A number of Loch Fyne's restaurants had already been converted from pubs - one, in the Surrey commuter town of Cobham, had been managed by Mr Derry in his previous incarnation as a publican. The hope was that various Greene King pubs among its 2,500-strong estate might go down the same route.

“I hadn't seen any of them, except to have a pint in,” Mr Derry says. “But I have faith that they know what they are doing.”

As well as supplying potential new sites, often the most difficult task in building a restaurant chain, Greene King provided the sort of back-house support - human resources, IT systems, “all the stuff that big businesses have that small businesses don't” - that the chain was starting to need.

Greene King paid £68 million, seen at the time as a high price. The VCs, however they may have grumbled, got their exit after two years. Loch Fyne now has its eyes on its first site in the City in Gracechurch Street.

Is this not time to slacken off? Restaurants are, after all, one of those items of discretionary spending that are the first to be cut out of the household budget. “At this stage, no,” he says. “Perhaps people will be more inclined to eat out less or spend less. I don't really believe they will stop eating out. We're not immune. But within this business we have a huge degree of flexibility. We can change menus overnight, we can change pricing,” he says. “You've got to roll your sleeves up and get stuck in.”

Mr Derry was raised in Crieff, Tayside, where his father worked for Bell's whisky. At school he was “a truly awful student” and his first part-time job was putting up fences on farmers' land. After a management training course he found himself, at 19, overseeing 60 staff supplying off-licences in Glasgow. After 18 months of that “I started work on an oil rig, because I thought it would be safer”. One senses that he is only half-joking. From the rig - “a month on, a month off; it was well paid but grim” - he wrote off for various jobs and landed one as a sales rep at Whitbread.

He ended up in marketing, spent time in New York and then was put in for a three-day management assessment. It was a disaster. “I came out of it and my career was pretty well over.” Thus pubs, and then fish.

Mr Derry says: “There's a lot of propaganda in the fish business, which is not brilliantly understood. There's absolutely no point in selling the last cod on the planet. People have to be more open-minded about farmed fish.”

The farms acquired a bad reputation in their early days for overcrowding and over-use of chemicals. “But if you do it well, there's a real impact on price. There's a balance between that and properly managed wild stocks.”

He recently received a most alarming letter from a customer. “My wife died at your restaurant on Friday.” Golly. Plus: “The oysters weren't as big as she had expected.” Were the two somehow linked? It was a typo. He meant “dined”. Says Mr Denny: “You don't get many complaints letter like that.”

Mark Derry

Born June 7, 1960, in Hereford

1983 Marketing director, New Ventures Group, Whitbread
1994 Joins Glenchewton, leads acquisition of Country Style Inns
1997 Launches Loch Fyne Restaurants
2003 Buys Le Petit Blanc from the administrators
2005 Sells Loch Fyne to Hutton Collins
2007 Loch Fyne bought by Greene King

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