Johnson, a no-nonsense 37-year-old whose business interests range from mussels to molars, characteristically tackles the subject head on. "I must say," he observes, when I first ask for an interview, "that your paper has written negative things about me in the past. I know my father brings out a particularly vitriolic hatred in some journalists and that this might rub off on me. But being his son is obviously not my fault."
Not that he has anything but love and gratitude for his parents. Amongst other things, they have taught him how to deal with publicity, fair and unfair. "It's all part of life and you shouldn't get too upset," he says, in a voice lower pitched than his father's and carefully classless.
Johnson is a large shareholder in Pizza Express and chairman of the Belgo group of restaurants, where waiters dressed as monks serve mugs of Belgian beer and dishes of steaming mussels, sausages andchips. He is in the news because Belgo has just spent pounds 9.3m on three South Kensington eateries of a peculiarly contemporary social status.
Daphne's, the Collection and Pasha are the kind of restaurants that appear in gossip columns and Hello! magazine, where show-business celebrities and the children of aristocrats go in the hope of being snapped by the paparazzi. They are not outlandishly priced - about pounds 40 a head on average - but nor are they universally admired.
The authoritative Harden's London Restaurants Guide reports one customer's view of the Collection as "overpriced and horrible" and notes the staff at Daphne's have a "breathtakingly rude attitude to non-celebs". The former owner, Danish-born socialite Mogens Tholstrup, will remain involved and, says Johnson, has ideas for expanding into new outlets.
Johnson is not buying the restaurants for want of somewhere to eat. "I've been to them but I wouldn't say I'm a typical customer. I'm probably too tight-fisted." A bachelor, he eats out all the time and is often seen at nightclubs, but he does not necessarily patronise his own establishments. "I like to try new places, to see what the competition is."
Restaurant proprietors come in two kinds. There are those motivated by a passion for good food. And there are the entrepreneurs who collect portfolios of such establishments because they are cash businesses with high profit margins that respond to economies of scale.
Johnson falls into the second category. "I'm certainly not a foodie," he confesses, although his first business venture was in the catering field. It started when, after leaving Langley Grammar School in Berkshire, he was a student at Magdalen College, Oxford. Keen on large parties - an enthusiasm he retains - he held them in his college rooms until the authorities banned them. He switched to an outside venue, charged admission, and made a modest profit.
On leaving Oxford he quickly ditched plans to become a doctor, deciding instead on a business career. After a spell with an advertising agency he went to work for Jonathan Aitken, the Conservative MP who then had an interest in TV-AM, the breakfast television station.
Paul Johnson is a noted defender of Aitken, who was formally charged last week with perverting the course of justice in the wake of his unsuccessful libel action against the Guardian. Does Luke share his father's view?
"Jonathan is the same as all of us. He has merits and he has flaws. It stands to reason that he was very ill-advised to bring this libel action but I don't think he's nearly as wicked as some people like to portray him. To an extent people like having a go at him because he went to Eton."
Johnson then joined a stockbroking firm as an analyst of media shares. This was where he began to meet the City's movers and shakers and soon he began to emulate them. Over time, he perfected the technique of the reverse takeover, which involves buying or creating a "shell" company, using it to acquire a profitable private business and then discarding the shell.
The takeover of Pizza Express in 1993 was a copybook example. With business partner Hugh Osmond he owned a small computer company, Star, which they used as a vehicle to buy control of the pizza chain for pounds 18m. When Pizza Express absorbed Star and was floated on the stock exchange, the investment more than doubled in value. Today Johnson's stake is worth some pounds 50m.
Not everyone in the city approves of these wheelerdealing games with paper. "Ruthless", "tacky", "canny" and "spivvy" are among adjectives used by some who have had dealings with him, none bold enough to speak on the record. He responds: "There are some British people who think there's something suspect about business altogether, and that if someone makes money there must be something wrong."
What about ruthless? "All reasonable people would prefer to avoid hurting anyone but business isn't a charitable activity. One of the problems that civil servants and politicians often have is that they think business is there to create jobs rather than to create a profit for its owners. I'm in business. I'm a capitalist. That speaks for itself really."
This muscular philosophy gets an airing every week in Johnson's column in the business section of the Sunday Telegraph, clothed in an overheated prose style that owes a lot to that of his father. "End this stifling tyranny of taxation" was the headline on last weekend's effort. "We have been battered for so long by grotesque levels of over-taxation that there is minimal real resistance," he wrote. "We fork out almost half our wealth to Whitehall incompetents ... How can any rational individual who believes in freedom suggest giving more money to the clowns in Westminster?"
Such intemperate views made him a natural recruit to the late Sir James Goldsmith's anti-European Referendum Party. He even agreed to stand as a candidate in west London at last year's election, though he stood down before polling day. "I was too busy on other things and I thought better of it," he explains.
His ambitions suffered another, more serious, setback when he sank more than pounds 200,000 into Sunday Business, the ailing weekly now owned by the Barclay brothers. He half-thought he might use it as a stepping-stone to more investments in print, but now admits it was a mistake.
"I lost all the money I put in, wasted a lot of time and probably ended up making enemies. But business is all about taking the plunge now and again. You do get it wrong and you just have to lick your wounds and start all over again."
Yet there have been more successes than failures. One of his most flourishing enterprises is Integrated Dental Holdings, a chain of about 350 National Health Service dentists. He also has holdings in Tecno, the photographic chain, and Topps, Britain's largest retailer of tiles.
Some of his partners in these enterprises are members of the Mandrake Club, a self-selecting group of high-flying businessmen that he founded with David Ross, a director of the Carphone Warehouse. Dubbed "the business brat pack", membership is strictly by invitation only. "The purpose was for David and I to have a place to meet like-minded people in business of roughly our own age. Sure, people have made useful connections and possibly formed partnerships there."
Inevitably, he has made enemies. One of his early partners was Stephen Hargrave, who went on to other posts in the City. "We don't do business together any more," Johnson admits. "We decided to go our own ways some years ago, for personal reasons." City rumour has it there was a dispute over a woman.
He admits he has a short temper, which he believes he inherits from his father. Certainly it does not come from his long-suffering mother. "It's amazing to think he's the son of the saintly Marigold," says an acquaintance.
He accepts that he is in many respects the opposite of his brother Daniel, who edits the Times's op-ed page. "Daniel's a much easier-going chap than I am in some ways and yes, he's considerably more intellectual and cultivated, I suspect." The contrast between the two men is well illustrated by their literary endeavours. Daniel is working on A History of German Thought. Luke's most recent work - written jointly with Osmond - is Betting to Win.
Although he has had many girlfriends, he has not married. His temper may be a reason why. In 1995 he was quoted as saying: "I am looking for a wife." But in the same interview he added: "I don't understand why women fall for men at all. I wouldn't blame women for being lesbians - they're much nicer than men generally."
Today his approach is different. "I suppose most people at some point want to get married but I feel no compulsion to do so." Many will hope the urge strikes soon. It would surely be a tragedy for the whole nation if this bloodline of opinionated iconoclasts were to end here.Reuse content