LONDON (AFP) - Olympic silver medallist Roger Black said he feels "a fool" after American sprinter Antonio Pettigrew, who pipped him to the 1991 world title, became the latest high-profile athlete linked to drug-taking.

"For me it's disappointing," the Briton told the Observer newspaper published Sunday.

"If he was taking drugs in 1991, he robbed me of being a world champion.

"When you looked around at your competitors I thought Pettigrew was clean. He was quick, but not super quick, and he was consistent over a long period of time."

Black, who went to win a 400 metres silver medal at the 1996 Atlanta Olympics, added: "I never thought he was on drugs... I feel a bit of a fool because you don't know what the hell is going on. You know what you did as an athlete and that you were clean. You assume that other people were clean as well. I feel very naive following everything that has come out recently."

Pettigrew beat Black into second place in the 400m at the 1991 world championships in Tokyo, but the American has recently admitted in US court documents that he was encouraged to take drugs by Trevor Graham, the coach of the disgraced Marion Jones.

Pettigrew, a four-time world champion who helped the US 4x400m relay win gold at the 2000 Olympics, was named as a user of performance-enhancing drugs in a witness list for the upcoming trial of Graham.

The New York Times reported Saturday that Pettigrew was identified on a government list of witnesses against Graham, whose trial on charges of lying to federal agents is scheduled to begin May 19.

Jones, who has been stripped of the five medals she won at the 2000 Olympics, is currently serving a six-month jail sentence after admitting she lied to federal investigators about her drug use.