Michael Phelps 'caught with cannabis pipe'

Eight-time Olympic gold medalist Michael Phelps is embroiled in a drug controversy, after News of the World published photographs of the American swimming superstar smoking what appears to be a bong.

The glass pipes are often used to smoke marijuana.

If the allegations prove correct, Phelps could risk his chance of adding to his medal tally at the 2012 Olympic Games in London.

The story claims Phelps partied for two days with students in November at the University Of South Carolina in Columbia, with one witness telling News of the World "he was out of control".

Reportedly Phelps knocked backed beers and shots of spirits, before being offered a bong from which he inhaled deeply.

"You could tell Michael had smoked before," the article reported a witness as saying.

"He grabbed the bong and a lighter and knew exactly what to do.

"He looked just as natural with a bong in his hands as he does swimming in the pool. He was the gold medal winner of bong hits."

The scandal doesn't stop there, the British newspaper also claims that Phelps' sponsors attempted to strike a deal for the damaging photos to be destroyed, including offering their client as a columnist for three years and other lucrative incentives.

This is not the first time Phelps has been in trouble with the law; in 2004 he was sentenced to 18 months probation for driving under the influence of alcohol.