There is something called “the design world” and it is coming to London. Should we be alarmed or delighted? Cautious, benign scepticism is my advice. But do be wary: “the design world” is an expression used only by the curious inhabitants of a self-regarding parallel culture that travels, relentlessly and remorselessly, from expo to furniture fair to festival, from Milan to Tokyo and then ultimately on to the Jerusalem of Clerkenwell, depositing objects that scream and clamour for attention on the way.

Four major exhibitions and salerooms of design arrive in the capital this month — Import-Export at the V&A, the London Design Festival, Design Mart at the Design Museum and 100% Design, with a number of satellite events whizzing off each — and they all prompt the question: why is “the design world” different from the real, undesigned world that everybody else inhabits? Visitors to the exhibitions, events, screenings, “ workshops”, seminars, talks, receptions, “showcases”, parties, trade shows, presentations and giddy round of exhausting self-promotions that comprise the London Design Festival will want to know.

“What is design?” has replaced “what is art?” as a reliable inspiration for post-prandial argument. The past offers some clues to help to interpret the present. Historically, design has meant different things in different countries. In Scandinavia, for instance, design became an expression of social-democratic purpose: the Swedish House Beautiful movement was paternalistic politics in the form of carefully wrought furniture and fabrics.

In Germany, design evolved as a disciplined, systematic approach to the style of industrial products. Meanwhile, in the 1950s and 1960s Italians sent brightly coloured plastic buckets as missionaries to New York’s Museum of Modern Art: design was propaganda for Italy’s postwar reconstruction. In America, on the other hand, design was meretricious innovation, next-year’s-model driving the dynamic economy down an endless freeway to geometrically enlarging prosperity. Or so the theory went.

Although Britain has a fine tradition of art education, the British have often found the notion of design faintly ridiculous. Evelyn Waugh had fun mocking the pretensions both of the modish flapper-decorator Syrie Maugham as well as the stern Bauhaus pedagogue Walter Gropius.

If the furniture and fittings of the Royal Yacht Britannia are meaningful evidence, nor does the Queen take design terribly seriously. Bevelled glass cocktail cabinets, plaited vinyl chairs with splayed metal legs, chintz, ditsy little things all over the place: council-house taste. And the future? 100% Design at Earls Court, the centre of the London Design Festival, provides some clues. With more than 450 exhibitors, the show claims, no doubt correctly, to be Britain’s definitive contemporary design show.

Certainly the rival Design Mart at the Design Museum, with its exhibit of “dynamic young designers” — you get through a lot of inverted commas writing about the design world — is a more modest affair.

The title 100% Design is a very revealing design-world concept. It betrays an exhausting full-on mentality, but is also suggestive of the zealotry and purity that define cult activities. What, one wonders, would a show called 80% Design be like? Earls Court, we are assured by the title, offers the purest strain of design. At the heart, then, of that flashing 100% must lie novelty. An idea of change is fundamental to design. And inevitably, with this idea of change comes a belief that the designer knows better.

Often in the past designers cited heightened efficiency and superior function as inspirations, but since manufacturing with its attendant disciplines of production engineering, cost-accountancy and materials technology has long since fled these shores, a very large percentage of that 100% is in all truth about neophilia and silly faddery. Not that neophilia and faddery are bad, but they do not guarantee permanent solutions.

There is one event in the London Design Festival that is genuinely provocative, as an idea if not as an exhibit. This is Import-Export, a British Council venture that originated, bizarrely, in Delhi. It celebrates how London — despite the indifference of Her Majesty, despite the apathy of the public and despite the lack of manufacturing industry to realise occasionally absurd dreams — has become the undisputed and unequalled creative capital of the planet.

Not since the 1930s, when Gropius and Breuer, Mendelsohn, Goldfinger and Mohoy-Nagy arrived from Nazi Germany to invigorate architecture and graphics, have there been so many design-world exotics in London.

A third of Europe’s design graduates were educated here. Most of them want to stay: the resource they want to exploit is not factories, which, of course, no longer exist, but the mobile, migratory, fast-evolving, wired, self-defining, clever, connected, buzzing network of creatives that has now achieved such very heavy critical mass that it has become a defining characteristic of national life. And an unquantifiably valuable economic asset, too: by one estimate, creative activities (it’s absurd to call them “industries”) are worth £21 billion a year.

London is a bloody, dirty, difficult, expensive place and that is what makes it great. The designer Gitta Gschwendtner says: “If I’d studied in Germany, I’d have had different expectations. I’d probably have ended up working for a company. Here I’m an industry of one.”