The Birmingham-based Irishman began working at Roach's Wild Card Boxing Club early this year, and the quality of the sparring took even a former European champion by surprise.

In fact, Macklin might still be in possession of the belt had a broken nose suffered in the States not scuppered a planned defence in the spring.

The 28-year-old has now been idle since getting past tough Uruguayan Rafael Sosa Pintos in a non-contest clash in December, but if Amir Khan's progress under Roach is any guide at all then there is basis to Macklin's claim that a new fighter will emerge on Sky Box Office on September 18.

Not that the boxer who decamped to California was too shabby, and Roach would have seen world-class potential in the way his new pupil destroyed Finland's Amin Asikainen to take the European title a year ago.

By that stage Macklin had already begun to temper the relentlessly pressing style which contributed so much to the famous British light-middleweight showdown with Jamie Moore in September 2006, chosen by Sky Sports' Jim Watt as one of his moments of the last decade.

Aggression alone failed to secure the belt that night as Macklin, whose only other defeat before or since came against Andrew Facey in November 2003 when the same title was on the line, needed oxygen following his 10th-round knockout at the end of a brutal contest.

Macklin immediately moved up a division and worked with Joe Gallagher to use his natural boxing skills as much as his appetite for a fight, a new-found blend which was eventually honed into the kind of controlled display which overhwelmed Wayne Elcock in March last year.

So impressive was Macklin on that occasion and in stopping Asikainen, the likes of Kelly Pavlik and Sebastian Sylvester were soon mentioned as potential opponents.

Instead, after being forced to vacate his European title, Macklin was matched with his successor as champion - long-time nemesis Darren Barker. Barker had attacked Macklin for pulling out of the pair's proposed 2009 contest to take on Asikainen, but this time it was the unbeaten Londoner who was forced to give up the belt because of a hip injury.

Macklin was forced to showcase his new skills against a new contender, Georgian Shalva Jomardashvili and although the late replacement made for a messy affair, he did the job in five one-sided rounds.

The boxing world is still waiting for Barker to happen but in the meantime Macklin does not intend hanging about in hope.