Nicola Adams is poised to turn professional after leaving the GB Boxing set-up ©Getty Images

GB Boxing has announced that double Olympic champion Nicola Adams has left their World Class Performance Programme (WCPP) and will not be part of their squad for the Tokyo 2020 cycle, with the boxer confirming she has turned professional.

Adams became the first female boxer to win Olympic gold when she overcame China's Ren Cancan in the flyweight final in front of a home crowd at London 2012.

The boxer then overcame Sarah Ourahmoune of France in the Rio 2016 final, making her the first British boxer since Harry Mallin at Paris 1924 to retain an Olympic title.

Adams has been released from her contract with GB Boxing, which was due to end on March 31, with the 34-year-old now turning professional.

She had previously confirmed talks about potentially joining the full-time ranks, but her first two professional fights have now been confirmed.

Adams is due to make her professional debut on April 8 in Manchester Arena before she competes in front of a home crowd in Leeds on May 13.

Opponent for both fights are yet to be confirmed.

Adams follow fellow London 2012 gold medallist Katie Taylor of Ireland and double Olympic champion Claressa Shields of the United States in leaving amateur boxing.

"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," said Rob McCracken, GB Boxing's performance director.

"She has won everything there is to win and her place in history is secured as the first woman 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."

Adams ends her amateur career as Britain’s most successful ever female boxer, having won the 51 kilogram world title in Astana last year, beating Thailand’s Peamwilai Laopeam in the final in Kazakhstan.

The triumph completed a career grand slam, after she previously won European titles, Commonwealth Games gold and the title at the inaugural European Games in Baku in 2015.

Adams was made an Order of the British Empire in the most recent New Years’ Honours list, while she was named the International Boxing Association female boxer of the year last month.