Video games might once have been considered a hobby for pale, sweaty teenage boys but they have now been accepted by the political and artistic establishment as a cultural phenomenon worthy of its own festival.

The London Games Festival kicked off last night with leading British and international artists, game designers and even government ministers joining forces to applaud computer games as a legitimate art form that deserves recognition from the wider public.

The week-long celebration began with a concert at the Royal Festival Hall featuring music from games such as Mario and World of Warcraft played by a classical orchestra.

Thousands are expected to attend the festival, whose highlights include the launch of keenly awaited new titles such as Guitar Hero and a “weatherproof stage” for people to try out new games in Trafalgar Square.

The computer games industry has grown dramatically and is approaching the size of the film industry with a worldwide revenue of $18 billion (£11 billion). “It’s not a surprise,” said Jonathan Yeo, one of Britain’s leading portrait artists who has painted subjects such as Tony Blair, David Cameron and the Duke of Edinburgh. “Computer games get most of the talented art graduates out of education who want to go straight into doing something visual but also get paid for it. I think in the future people will look back and study computer-game design of this period as being a phenomenally creative one, and possibly just as important as the other visual arts.”

Prominent international artists such as Cory Arcangel, whose work has been exhibited at the Guggenheim Museum and the Museum of Modern Art in New York, have been influenced by games. His installationSuper Mario Clouds was made by “hacking” game cartridges to remove everything but the clouds from the game.

“A lot of interesting things are happening in games,” said Jaime Gili, a Venezuelan contemporary artist who has been commissioned to create one of the largest public art works in the world – an installation that involves painting 16 huge petrol tanks in Maine in the United States. “I don’t like it when they do Hollywood remakes of games, but games like The Sims are art straight away,” he said.

Prominent game designers, hailed as visionaries within their industry, said that they were often met with scepticism by the wider public.

“It can be misinterpreted if we claim games as art, when in reality what we’re making is entertainment,” said Owen O’Brien, senior producer on the forthcoming Mirror’s Edge. “But if movies and music can be considered art, games could justifiably be as well.

“If art is something that stirs the emotions, then I think and hope that is something computer games do.”

Politicians were once largely sceptical about games because of the perceived malign influence they had over children. But the games industry has become accepted across the political divide, thanks in part to its growing financial clout. Last year 78 million video games were sold in Britain, with a total sales value of £1.72 billion. Britons spent £435 million more on games in 2007 than on buying music CDs.

Both the Government and the Mayor of London, Boris Johnson, gave their backing to the festival. Mr Johnson, who has contributed significant funding to the festival through the London Development Agency, said it “demonstrates the creativity and range of the gaming industry, which is an important part of London’s creative sector and makes a vital contribution to the economy as a whole”.

Barbara Follett, the Minister for Culture, said: “Britain has one of the most successful video-games markets in the world and the London Games Festival is a celebration of the creativity, expertise and flair that has made it so.”