Undefeated world super-middleweight and light-heavyweight champion Joe Calzaghe has announced his retirement.

The 36-year-old Welshman, who reigned as a world champion for more than 11 years, quits the ring with a glittering record of 46 wins from 46 fights.

"It was a difficult decision but I have achieved everything I wanted to achieve in boxing," he told BBC Sport.

"I've been world champion for 11 years. I've got no other goals to go for. That's why I am calling it a day."

In an exclusive interview with BBC sports editor Mihir Bose, Calzaghe, who held the WBO, WBA, WBC and IBF super-middleweight belts during his 16-year professional career, said he had thought "long and hard" about retiring but insisted it was the right move.

"I had a long think with my family," he said. "My children wanted me to give up, plus my mum. That's why I called it a day and will go on to do something else."

BLOG Calzaghe deserves to sit alongside Ken Buchanan and Lennox Lewis as the greatest of Britain's post-war greats BBC Sport's Ben Dirs

Asked if he could ever be tempted back into the ring in the future, the Newbridge fighter replied: "My decision is to retire. I've been boxing for 25 years and, like I said, I've achieved everything I want to achieve.

"You can never say never in this game, but I can't see myself boxing again. There's loads of things I want to do. I'm proud to be one of only a few fighters in history to retire undefeated."

Calzaghe, who was born in London but moved to Wales when he was two, chalked up an impressive record as an amateur, winning 110 of his 120 contests after taking up the sport at the age of nine.

He began his professional career with a first-round stoppage of Paul Hanlon on 1 October, 1993, going on to win seven of his first nine bouts in round one.

Trained by his father, Enzo, he became British super-middleweight champion in 1995 before capturing his first world title in 1997, outpointing Chris Eubank to claim the WBO crown.

Calzaghe poses with the WBO and WBC super-middleweight betlls

He then claimed the WBA and WBC belts with what he feels is his most satisfying fight, a unanimous points win over Denmark's Mikkel Kessler at the Millennium Stadium in Cardiff on 4 November, 2007.

"Unifying the super-middleweight division in front of 50,000 fans was a dream come true for me," he told BBC Sport.

"I was fighting a younger fighter than me, I was the underdog. A lot of people thought I was going to lose that fight. It was a great night."

Just a few weeks later, he was named BBC Sports Personality of the Year, collecting a CBE soon afterwards, which went nicely along the MBE he received in 2003.

Calzaghe's final two fights cemented his reputation as one of Britain's greatest ever boxers.

Stepping up to light-heavyweight and fighting in America for the first time, he won a split decision against Bernard Hopkins in Las Vegas to become 'The Ring' light-heavyweight champion.

He then finished his career with a comprehensive points victory over the legendary Roy Jones Jr at New York's Madison Square Garden on 8 November.

Calzaghe, who will be 37 on 23 March, hinted before the fight with Jones that it would be his last, despite talk of a re-match with Hopkins.

Fellow Briton Carl Froch, who took possession of Calzaghe's old WBC super-middleweight belt by beating Canadian Jean Pascal in December, was also eager to take him on.

But Calzaghe resisted the lure of another big pay day and the chance to inch closer to Rocky Marciano's record of 49 wins from 49 fights.

Calzaghe, who has two sons, Connor and Joe, from his marriage to Mandy, says he now plans to concentrate on his charity work and becoming a boxing promoter.

Now divorced and living with model girlfriend Jo-Emma, he also revealed he had several TV projects lined up.

Heavyweight champion Rocky Marciano with 49 wins in 49 fights and strawweight and light-flyweight Ricardo Lopez of Mexico, with 51 wins in 51 fights also retired undefeated.