Amir Khan has to lose the bad habits that he developed as an amateur to make it to the top as a professional, Frank Warren, his promoter, says. Khan won a silver medal at the Olympics in Athens four years ago, but Warren believes that he has plenty to learn before he boxes for a world title.

Khan, 21, goes for his nineteenth consecutive win as a professional when he faces Breidis Prescott, an unbeaten Colombian, at the MEN Arena, Manchester, on Saturday. The week after, in Biloxi, Mississippi, Nate Campbell defends his WBA, WBO and IBF lightweight titles against Joan Guzmán. Khan, the Commonwealth lightweight champion who is rated No2 by the WBO, should be next in line for the winner, but while he has been impatient to box for a world title, it will be 2009 before Khan competes in such exalted company.

Warren believes that Khan's success as an amateur has hampered his development as a professional. “Amateur boxing is so different from the professionals, it takes time for boxers turning over to adapt,” Warren said. “Most of the top amateurs who have turned over tend to be very upright and they tend not to throw body punches.

“Not boxing three-minute rounds and using headguards does not help, either. Headguards were developed by professionals to stop them getting cut during sparring. But it just makes the head a bigger target, so they don't slip punches as much. It doesn't lessen the impact of punches, but some box like they think they make them invincible.”

The knockdown that Khan suffered against Michael Gomez in June set alarm bells ringing that Khan may not be equipped for the professional ranks yet. Prescott, 25, has won all his 19 bouts, 17 by stoppage, ensuring that he is likely to give Khan a severe test.

Saturday's bout will be Khan's first with his new trainer, Jorge Rubio. While Rubio's roots are in Cuban amateur boxing, Warren believes that the first signs are good. “He's talking about the need for Amir to move his head and sit down on his punches more,” Warren said. “It will take time for the two of them to get to know each other, but if Amir wins next week, he will probably box late in November or in December. Then next year we can talk about a world title.”

Warren fears that the seven boxers that qualified for the Olympics could have problems conforming to the professional code. The return of one gold and two bronze medals from Beijing was the best performance by Great Britain since the Melbourne Games of 1956. But, as Audley Harrison showed after winning super-heavyweight gold in Sydney, amateur success does not guarantee success in the paid sport.

“A couple of them are very interesting, but some of them will struggle to adapt,” Warren said. “Years ago it was different. The two codes used to be more similar and boxers were ready for the pros when they turned over. For some now it is like two different sports.”

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