Two-time Olympic champion Nicola Adams has signed a long-term promotional deal to turn professional with Frank Warren.
The boxer left the world class performance programme on Monday morning and will now work with Warren as she starts her professional career.
Adams will make her professional debut at Manchester Arena on April 8, before a homecoming fight at Leeds Arena on May 13.
The double Olympic champion has been released from her contract and will not be part of the squad for the build-up to the 2020 Tokyo Games.
GB Boxing performance director Rob McCracken said: "Nicola has made a huge contribution to both the Olympic programme and the sport of boxing and I would like to thank her for everything she has done for GB Boxing since she joined the squad in 2010."
Adams follows fellow Olympic gold medallists, Ireland's Katie Taylor and US star Claressa Shields, in fighting the rest of her career in the professional ranks.
Having swept to her second consecutive gold medal in Rio - becoming the first British boxer since 1924 to retain an Olympic title - there seemed little reason for the Leeds fighter to commit to another four years on the GB programme.
She had also secured a clean sweep of career major titles earlier in 2016 when she defeated Thailand's Peamwilai Laopeam to win her first world title in Kazakhstan.
Adams was the first female boxer to fight for England in 2007 and she went on to win European and Commonwealth titles after battling back from a career-threatening back injury in 2009.
Despite the advent of professional boxers at the Olympics, the move effectively ends Adams' chances of going to Tokyo, with GB Boxing making clear it will favour athletes who remain on its full-time programme.
McCracken added: "Nicola has won everything there is to win and her place in history is secured as the first women to ever win a gold medal for boxing and then top it by winning a second one in Rio.
"She is a superb ambassador and has been a significant part of the success we have enjoyed at GB Boxing in the last eight years.
"We would have welcomed Nicola staying on for the Tokyo cycle, however we recognise her decision to pursue other opportunities and wish her every success in whatever she goes on to do next.
"Nicola will remain part of the GB Boxing family and will always receive a warm welcome whenever she visits our gym in Sheffield."