Delpopolo (pictured above), who was making his first Olympics appearance in London, tested positive for marijuana after, what he claimed, was accidental consumption of the substance before the Games, and has had his accreditation for London 2012 revoked immediately.

The 23-year-old finished seventh in his competition, with his hopes of winning a medal ended last week by Mongolia's Nyam-Ochir Sainjargal.

The American had enjoyed a good Olympics despite failing to win a medal, and received a bye through the first round.

The Pan American Games bronze medallist thrashed his first opponent Chi Yip of Hong Kong with two ippon.

In the second round he beat Belgium's Dirk Van Tichelt by yuko, before putting on a sterling performance against South Korean world number one Wang Ki-Chun.

"My positive test was caused by my inadvertent consumption of food that I did not realise had been baked with marijuana, before I left for the Olympic Games," Delpopolo said in a statement.

"I apologise to United States Olympic Committee (USOC), to my teammates, and to my fans, and I am embarrassed by this mistake.

"I look forward to representing my country in the future, and will re-dedicate myself to being the best judo athlete that I can be."

Victoria Baranova was sent home from London 2012 after testing positive for testosterone

Delpopolo is the latest athlete to be kicked out of London 2012, following positive drugs tests from Colombian runner Diego Palomeque Echevarria and Russian cyclist Victoria Baranova at the weekend.

The IOC, which is conducting 5,000 tests during London 2012, has now suspended five athletes since the start of the Olympic period on July 16, while others have been sent home by their own countries following failed drugs tests.

This weekend also saw the controversial return to the Olympics for British sprinter Dwain Chambers, America's Olympic 100 metres gold medallist Justin Gatlin, and his compatriot reigning 400m Olympic champion LaShawn Merritt, who have all served bans for failing drugs tests in the past.

While Chambers failed to get beyond the London 2012 100m semi-finals and Merritt dropped out of the Games after sustaining a hamstring injury, Gatlin took the 100m men's bronze medal at last night's final in the Olympic Stadium.

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