Warning: graphic content - how a new wave of illustrators is blowing the art world apart

On a bright Saturday afternoon at the end of April, 10 groups gather in the bowels of Somerset House to take part in a show. Their names sound like rock bands: Nous Vous, Evening Tweed, Le Gun, Landfill, Concrete Hermit, and they've got the look too – all directional fringes, tight trousers and ironic facial hair.

There's not a twanging guitar to be heard in this grand Thameside venue, though, for this is an artistic venture of a different kind – a series of rooms, filled with wildly imaginative art prints, illustrated T-shirts and comic books created by a hotchpotch of underground collectives, galleries and solo artists.

Pick Me Up is Britain's first contemporary graphic-art fair and, on this particular day, the place is thronging with 2,000 visitors – but it still has an underground feel, as if these kids showing their wares, demonstrating their arcane printing techniques and exchanging creative ideas are part of a cultural phenomenon just waiting for lift-off.

The work itself is extraordinary: everything from dizzying Op Art to intricate paper cuts and lovingly typeset slogans to illustrations of fantasy creatures. There are themed rooms – one is set out as a country manor house, another contains a pair of gigantic white buttocks. It's a long way from sportswear logos or cornflake-packet rebranding. And that's what makes this show so remarkable – while everything within in it is steeped in the language of traditional, commercial graphic design and illustration, the work has been created purely for its own sake: it's gone feral.

As the design writer Adrian Shaughnessy says: "Graphic design used to be this robust thing where designers wore red spectacles and talked about business. But now there's been this extraordinary explosion where they are speaking the language of self-expression and personal projects."

The artists at Pick Me Up are just the tip of an iceberg whose centre is probably located somewhere beneath the chewing gum-spattered pavements of Shoreditch or Dalston in east London. For these are the heartlands of a buzzing community of design and illustration graduates who, alongside their commissioned work, exhibit, collaborate, run print workshops and share news and ideas among themselves via a zillion earnestly compiled blogs.

It is the same home turf as the graffiti writers. And if Banksy and his fellow street artists were the popular art movement of the first decade of the 21st century, perhaps this lot are their successors. Anthony Burrill, the much-revered graphic designer responsible for creating all the signage for Pick Me Up, likens the scene that has developed in the past five years to the early days of punk rock.

"When I graduated from the Royal College in 1991 there was nothing like it at all. People leave college now and they're much less likely to get a job in a design company; there's more opportunity to set up your own thing. Everyone's got little shops on their website – I sell quite a lot of stuff off mine – and it just feels quite punk rock, doing our own thing."

Burrill himself was one of the first graphic artists to start selling his own work directly to the public – his Work Hard and Be Nice to People print, made using traditional woodblock techniques, continues to shift online by the bin-load, and is a good example of the curious mix of 21st century and olde-worlde technology that underpins this scene.

"Before, as a designer, there were 100 different processes you had to understand and maybe five or six people you had to work with – film-setters, plate-makers and so on," explains the designer Robert Green. "Now everybody has a graphic-design programme on their computer, and it's devalued and demystified our work."

The result is that, in the commercial world, the era when graphics gods such as the late Alan Fletcher (who created, among many others, the current logo for the V&A museum) and Neville Brody (the founding art director of The Face magazine) would be given carte blanche by their clients to interpret a brief as they fancied has been succeeded by one of rampant committee-ism – now everyone has an opinion. "Designers are looking for ways to reclaim authorship," Green says, "so they are diversifying, finding their own products to sell; and, because a lot of the old processes are disappearing, there's an urge to go back to them – screenprinting, for example, which, though it has a certain authenticity, is really a redundant technology in the age of digital prints."

The question, though, is once graphic art stops being about selling a product and starts to be about selling itself, is it graphic art at all? Have all these collectives and print-makers stumbled accidentally into the realm of fine art?

Design historian and curator Emily King is not convinced. "There's a very culturally specific distinction between fine art and graphic art," she says. "Fine artists need representation, there's the whole gallery and museum system, whereas for an illustrator, with the internet, they don't even need an agent to get their work out there. Also, when people work in the fine-art sphere, they think about the history of fine art and the current state of fine art. People making illustrative work are probably equally aware, but of a completely different set of practices and histories – they're different but equal."

The self-supporting graphic-art scene that's flowering now has its own back-story. It was the music business that first really allowed graphic artists off the creative leash; from Milton Glaser's kaleidoscope-haired Bob Dylan poster for CBS in 1966 through to Peter Saville's emotive imagery for Factory Records in the early 1980s, by way of some far-out Pink Floyd gatefolds. As King notes, "Even at the end of the 1980s people went into graphic design because they wanted to produce record sleeves, and that link sadly faded away when vinyl disappeared."

With this avenue of free expression shut down, graphic artists moved over into the rag trade. During the 1990s, the likes of James Jarvis and Fergus Purcell helped create a new trend for limited-run printed T-shirts. At the same time, bookshops such as Magma had started selling monographed design products, and a new breed of graphic-design nerds and collectors was soon multiplying. Once the internet arrived, there was no stopping them.

The top blog now is arguably It's Nice That, which was set up three years ago by Will Hudson and Alex Bec, two students at Brighton University."It started off as a project I was doing on my graphics course," says Hudson, "leaving cards on people's work, paying them a compliment. Then it got connected online and it's grown organically ever since. Now we're getting much more into curating shows and have set up our own design studio too."

You need only trawl through the site to see the sheer volume of work out there – perhaps not surprising when you consider that there are 10,000 more design students in Britain than 10 years ago. For the curious outsider, it can be hard to know how to filter it all, and it was partly with this in mind that six months ago I began to organise an exhibition and website showcasing some of the most influential and forward-thinking names in contemporary graphic art – especially those connected to the worlds of music and fashion.

It opens next week and features the work of young guns such as the 24-year-old wunderkind Kate Moross, who has already produced her own capsule collection for Topshop, alongside older heads including Lizzie Finn and Klaus Haapaniemi, who are helping inspire a new generation. For the exhibition, each artist has created a piece loosely themed on the subject of London, reflecting the incredible range of styles out there, from edgy line drawings to hypnotic abstractions. You can see some examples on these pages.

The great American author Tom Wolfe once said: "Art historians 50 years from now will look back upon illustrators as the great American artists of the second half of the 20th century." You don't need to have a directional haircut or tight trousers to suspect that such a sentiment might apply to the creative movement that's stirring right now in the heart of our capital.

Outline Editions' 001 London is at 7 Marshall Street, London W1, from 28 May to 3 July. Children's illustration workshops will run throughout the show. For more details: 020 8451 3400

Reader offer

Outline Editions is pleased to offer readers of 'The Independent on Sunday' an exclusive opportunity to collect the artwork on show at 001 London. Signed, limited editions are available to buy from outline-editions.co.uk , priced from £85 to £145. Readers can benefit from a 15 per cent discount by typing 'Indie Offer' into the discount code box on the shopping cart page. Offer valid until 7 June. For full terms/conditions, call Outline Editions on 020 8451 3400