Olympic gold medallist Anthony Joshua will finally turn professional this week after leaving the Great Britain amateur boxing programme with immediate effect.

The 23-year-old, who has not fought since his thrilling super-heavyweight final victory over Roberto Cammarelle in London last summer, is set to sign for Eddie Hearn's Matchroom organisation.

It means Joshua, who fights out of Finchley, could make his debut on the undercard of Carl Froch's world super-middleweight title clash with George Groves later this year, which is being promoted by Hearn.

The British Amateur Boxing Association said in a statement: "[BABA] has confirmed that the 2012 Olympic super-heavyweight gold medallist, Anthony Joshua MBE, will not be part of the GB Boxing squad in the 2013-17 Rio cycle.

"His contract with the BABA finished at the end of the 2009-2013 London Olympic cycle and he has now left the World Class Performance Programme to pursue other career opportunities."

Great Britain performance director Rob McCracken said: "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.

"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."

Joshua had been training at the Great Britain squad's gym at the English Institute of Sport in Sheffield while he considered his options in the wake of his Olympic triumph.

They included interest from both Matchroom - who recently signed Joshua's fellow gold medallist Luke Campbell - and Oscar De La Hoya's Golden Boy organisation in the United States.

Great Britain chiefs had harboured the increasingly slim hope that Joshua would elect to stay amateur and sign up instead for the new APB series run by world governing body AIBA.

But the recent axeing of the British Lionhearts franchise from the World Series of Boxing effectively ended any possibility of Joshua deciding to remain in the amateur ranks.

Furthermore, the Amateur Boxing Association of England is currently under a provisional suspension by AIBA, leaving English boxers' future participation in major tournaments in doubt.

Joshua will not be short of future targets in a burgeoning domestic heavyweight division headed by David Haye and Tyson Fury, who meet in Manchester at the end of September.

But Joshua's new backers will be keen not to rush him through the ranks. He only joined the Great Britain podium squad in 2010 before winning a World Championship silver medal the following year.

Joshua is be the fourth member of Great Britain's 2012 Olympic boxing team to turn professional, following Campbell, middleweight bronze medallist Anthony Ogogo, and Thomas Stalker - the latter pair with Golden Boy and Matchroom respectively.