Cake won the account after a competitive a pitch.
The agency worked with B&J's last year on its 'Sundae' music festival in Clapham, an event designed to mark the brand's tenth anniversary in the UK. A similar event is planned for 2006.
Revolver, which was hired in July 1998, described the end of its reign as amicable. But the loss comes at a turbulent time for Revolver: it emerged this week that MD Trudi Smith has left, just two months after being promoted to the role.
Smith said: 'I have no plans confirmed at the moment.'
Her exit comes just two months after founding MD Martin Ballantine and head of guerrilla marketing Damon Statt quit the agency (PRWeek, 18 Nov 2005).