When Darren Barker announced on Wednesday that he was retiring from boxing, his decision to bring an end to his career wasn't questioned. That wasn't because the former IBF middleweight champion couldn't cut it at the top level anymore, it was because he had earned the respect of the public for completing a true underdog story.

In the record books, his defeat to Felix Sturm will read as a second-round stoppage with two knockdowns, but you have to delve deep into the story of the Barnet-based boxer to appreciate that he had taken himself to the limit to give himself a lucrative opportunity in Stuttgart in the final month of 2013.

Barker turned professional in 2004, and after putting together seven wins in the first 15 months in the paid ranks, he blitzed his way through a further seven encounters, ending his time in the ring in 2006 by stopping two opponents inside the first round.

However, two days after his 14th win, his brother Gary was killed in a car crash, which understandably resulted in boxing being placed very much in the background as he contemplated whether he retained a desire to compete in a sport where he had shared the day-to-day rigours in the gym with his sibling.

Barker's return to the ring came nine months later, and after he defeated Greg Barton in three rounds, he secured the vacant Commonwealth title with a gutsy performance over the previously unbeaten Ben Crampton.

That triumph resulted in almost two years of defending his Commonwealth strap against a series of challengers who were a class below the Londoner, but the scalps that he had added to his record secured an opportunity to fight for the vacant European title, which he dug deep to claim against Frenchman Affif Belghecham.

It was after the Belghecham win that things began to change for Barker. He had been forced to undergo hip surgery earlier in 2010 before a highly-anticipated domestic showdown with Matthew Macklin was agreed for September, but less than a month before the fight, Barker broke down with the same hip injury for a second time, and the match was ultimately shelved.

It was another year before Barker stepped back through the ropes to reclaim his European belt, and while the Brit would have probably preferred to continue his rebuilding process, he was granted the chance to compete for world honours against Sergio Martinez in Atlantic City. Barker has since admitted that he didn't have the belief to beat the legendary Argentine, but it was an opportunity that was impossible to turn down.

Barker competed gamely against Martinez, having some relative success during the early rounds, but he was ultimately outclassed by the South American, who pummeled the Brit into a stoppage in the penultimate round, and the defeat resulted in another year out of the sport for 'Dazzling'.

His world title challenge had represented his first match under the guidance of Matchroom Sport, and he returned to the ring as a man on a mission, blasting out both Kerry Hope and Simone Rotolo in four rounds to elevate him back onto the global scene.

Promoter Eddie Hearn delivered a shot at the IBF title of Daniel Geale, who had been regarded as one of the weaker world champions at 160lbs. However, no-one could envisage the type of battle that occurred in Atlantic City, as Barker produced a display that capped an emotional journey from Southern Area titlist to world champion.

Geale's reputation was on the up in a competitive division, but Barker met the Australian in the middle of the ring for a fight, which hadn't been his style during the previous nine years of his career. But the 31-year-old was getting the better of the champion, who looked slightly stunned at Barker's heart when sat on his stool just before the midway point, but that desire was tested in a memorable sixth round.

Geale landed a brutal body shot that sucked the life out of Barker, but with the memory of his brother in his mind, the challenger rose to his feet at the last possible moment to offer a riposte that, at the time, didn't appear human. After 20 seconds of unanswered punches, the Londoner fought back and ended the three minutes savouring the adulation of the American crowd.

The remainder of the fight was fought in the same fashion, on instinct rather than any specific gameplan, and Barker was given the split-decision victory that immediately reduced him to tears, a sign that his dream had been realised after the toughest of professional careers.

In the aftermath of his win, Barker was outspoken about his quest to take bouts with Martin Murray, Macklin and Gennady Golovkin, but in reality, the job had already been completed. He undoubtedly wanted to end his stay in the sport on a high with a win against Sturm, but the drive to beat the German wasn't the same as it was before attempting to reach the pinnacle of his career against Geale.

Despite losing to Sturm in such circumstances, the manner in which his hip broke down for a third time leaves Barker with no doubts that he has reached the correct decision, and as he admitted during his interviews yesterday, he leaves boxing as a "happy man".