The start-up has a board of five, with Granger currently the only employee. Its founding clients are Central Bedfordshire University Technical College and the United World Schools charity. The agency will be staffing up the Birmingham operation in the "near future".
Granger joined Red Bull Racing, the Formula 1 racing team, in 2007, two years after launch. he left on 14 September. He was part of the team which pioneered the use of social media to build the brand.
He said the agency will focus on helping clients take social media in house, rather than treating it as a PR channel, and guiding them through the process.
Red Bull was forced to postpone its supersonic skydive yesterday, due to weather conditions.Follow @shearmans