Job: chief executive, Mind Candy
Age: 38
Industry: digital media, games
2012 ranking: 44

He has been described as a "rock star version of Willy Wonka" and London's "unofficial ambassador for tech success".

Michael Acton Smith, the founder and chief executive of Mind Candy, has made a fortune out of his global kids' phenomenon, Moshi Monsters, the virtual pet and social networking game with more than 80 million users in 150 countries worldwide.

Smith, who has a slide and a treehouse built into his offices (which are carpeted with Astroturf) founded Mind Candy in 2004, launching Moshi Monsters four years later.

The first online community for children, Moshi Monsters has since expanded into toys, publishing, music, TV and a live tour – with long-mooted plans for a big screen outing as well. However, Smith admitted earlier this year that the company was caught by surprise by with the speed at which children were switching to mobile.

Smith previously launched gadget website Firebox although another project, his elaborate global treasure hunt Perplex City, was a costly flop.