Jamaican sprinters Asafa Powell, the former 100 metres world record holder, and Sherone Simpson have had their doping bans reduced from 18 months to six months and are free to compete immediately, the Court of Arbitration for Sport has announced.

The pair were suspended by a Jamaica Anti-doping disciplinary panel after testing positive for the banned stimulant oxilofrine.

They appealed to CAS to have their bans reduced to three months and the appeals were partially upheld. As the six-month bans have already been served, they are now eligible to compete.

Powell immediately expressed his relief on Twitter saying: “Thank u to The Court of Arbitration for Sport. Finally this weight has been lifted off my shoulders. Justice has been served. Now let’s run!”

The 31-year-old then added he would make an instant return to the track in Lucerne tomorrow.

The reduction of the ban — given after he tested positive at the Jamaican national championships last summer — means he can return ahead of his scheduled date of December.

Powell, who held the 100 metres world record between 2005 and 2008, had initially expressed his unhappiness at the ban, saying in April: “This ruling is not only unfair, it is patently unjust.

“Panels such as these, I understood, were assembled to allow athletes who consciously or unconsciously come into conflict with the rules of sport a chance at equitable redemption. Unfortunately, this was not the case.”

Powell claimed that he took a legal supplement, Ephiphany D1, which was contaminated with oxilofrine.

He added: “I want to reiterate that I have never knowingly taken any banned substances. I did all the necessary checks before taking Ephiphany D1 and it is my hope that the CAS will prove to be a more open and fair avenue for the review of all the facts in my case — facts and truth that were not taken into consideration at my initial hearing.”

His wish has now been granted but, like Simpson, he will miss next week's Commonwealth Games in Glasgow with the Jamaican squad having already been selected during their suspension.

Like Powell, Simpson tested positive in last summer’s Championships and blamed the positive result on a supplement given to her by a training partner. She had initially been suspended until December 20th.