Sir Tim Berners-Lee and Sir Richard Branson have linked up with Google to find Britain's most innovative social entrepreneurs.
The pair are on the lookout for not-for-profit organisations that could use technology to transform lives.
They will select the most impressive projects as part of Google's £2m Global Impact Challenge which will see the four strongest contenders handed a cheque for £500,000.
Sir Tim said: "The web's contribution to economic progress has been much celebrated, but I believe that we are only scratching the surface of its potential to solve social and political problems."
Sir Richard said the competition could lead to a "new wave of innovation".
"I am a great believer in the power of entrepreneurs to solve key problems and improve lives through a combination of free thinking and the intelligent use of technology," he said.
"Google's Impact Challenge is a brilliant way to spark a new wave of innovation amongst non-profit foundations and charities and raise the profile of many great ideas in the non-profit sector."
The two entrepreneurs will be joined on the judging panel by Matt Brittin, Google's vice president for northern and central Europe, Jilly Forster, founder of campaigning agency Forster Communications, and Jacquelline Fuller, director of Google Giving, the internet giant's philanthropic arm.
Ten finalists will be announced in May before the winners are selected in June.
Alongside their cheques, the final four will be handed Chromebook computers and offered technical assistance by Google to help launch their ventures.