Anthony Joshua
Joshua will turn professional nearly a year on from his gold medal success at London 2012. (Reuters)

Nearly a year on from his gold medal success at London 2012 super heavyweight Anthony Joshua has left the amateur boxing programme , the British Amateur Boxing Association have confirmed.

The 23-year-old is expected to sign his first professional deal with Eddie Hearn's Matchroom Promotions after the group announced their plans to hold a press conference in London on Thursday, where Joshua is expected to join fellow Olympians Luke Campbell and Tom Stalker in Hearn's stable.

The BABA confirmed that the Finchley-born fighter will not be part of Great Britain's plans for the 2016 Olympic Games in Rio.

"Anthony is a very talented sportsman who has enjoyed a meteoric rise to become Olympic champion, less than four years after he first began boxing," Great Britain performance director Rob McCracken said.

"Naturally, it is a disappointment for us that Anthony has decided his future lies away from the GB Boxing programme, but he departs with our very best regards and we wish him every success in his future career."

"As we enter the Rio cycle, six of the 10 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."

Following the announcement, Joshua was quick to thank -through his Twitter account - those who have helped him progress through the amateur ranks to the cusp of professional boxing.