Luke Campbell is expected to turn professional after the British Amateur Boxing Association confirmed the 25-year-old would not be defending the Olympic gold medal he won last year.
Campbell was one of the success stories in amateur boxing after his triumph in the bantamweight division at London 2012, beating Ireland's John Joe Nevin in the final.
He was awarded an MBE in the New Year's Honours List but will not be part of the Great Britain boxing squad for the 2016 Rio Games after his contract with the BABA came to an end.
Instead, he is being widely tipped to join Eddie Hearn's Matchroom stable, with the promotions company last week calling a press conference for Tuesday to announce a major signing.
BABA performance director Rob McCracken said: "Luke has been a great servant to the World Class Performance Programme for a number of years and an excellent role-model to other members of the squad in both his medal-winning performances and the way he conducts himself inside and outside of the gym.
"It is a disappointment for us that Luke has decided his future lies away from the GB Boxing squad but he departs with our best regards and we wish him every success in his future career.
"As we enter the Rio cycle, the majority of the boxers that competed in London remain part of our squad and we have some excellent talents coming through so the programme has a strong nucleus to work with and a good opportunity to add to the success we have enjoyed in recent years."
Campbell, who joined the GB Boxing squad in 2007, will join Anthony Ogogo and Tom Stalker from Britain's 2012 squad in the paid ranks.