Tim Montgomery, the disgraced former United States athlete, has been sentenced to five years in prison after admitting to heroin charges in Virginia.

The former Olympian, 33, was found guilty of conspiracy to possess more than 100 grams of heroin with the intent to distribute the drug. He entered his guilty plea in July under an agreement with the US Government.

He will serve the five-year term after completing a four-year prison sentence he is serving for his role in a check-fraud conspiracy in New York. A contrite Montgomery apologised to Judge Jerome B. Friedman at his hearing.

US Drug Enforcement Administration agents said Montgomery sold 111 grams of heroin to an undercover informant for about $8,500, with the authorities recording on video four meetings between Montgomery and the informant.

Montgomery won Olympic gold medal in the 400-metre relay at the 2000 Games, a silver in the same event four years earlier and broke Maurice Greene's 100-metres world record in a time of 9.78sec in 2002.

However, he was stripped of each achievement and issued with a two-year ban from athletics after he admited to investigators in the Balco doping scandal that he used a once-undetectable steroid.