Hamlin, the media and commercial director, is understood to be in negotiations with Aegis, Carat’s owner, to work with its clients.
Hamlin is working out his notice as a Carat employee, before taking up his full-time managing director role at Inside. Aegis also owns Carat sister agency Vizeum and outdoor agency Posterscope.
Its new company will aim to emulate the Adidas mobile football portal, which launched in March and serves the UK, Germany, France, Italy, Spain, China and the US.
He was instrumental in setting up a global football portal on mobile for Adidas.
The service offers free Premiership alerts, results, tables and fixtures to users via mobile and will be providing information for the forthcoming World Cup.
Adidas has estimated that by the end of the tournament, its branded portal will have become the most successful off-network mobile portal in the world. It hopes to secure 500,000 visits, 1.5 million impressions and 600,000 downloads by the end of the World Cup.
Hamlin declined to comment.