The 52-year-old earned victory at the Games in South Korea representing East Germany, at their final Olympics before re-unification.

In an upcoming biography, Schenk wrote that he had taken banned steroid turinabol while an athlete.

He stated he was at first unaware of taking a banned substance, but later realised.

He references being giving pills at a training camp at Belmeken in Bulgaria.

"I was doping, and I knew that I dope," Schenk wrote in extracts published by Bild.

"At first I denied having ever taken any banned substance, and then I settled for the somewhat softer legal answer that I never knowingly doped, both of which was a lie.

"In Belmeken, I experienced a variety of pills being poured out on the plates of the athletes during mealtimes.

"We called them Smarties, but we did not know exactly what we swallowed - it was supposed to be vitamins and minerals."

Schenk won gold at Seoul 1988 in front of his team-mate Torsten Voss and Canada's Dave Steen, who completed the podium.

Britain's Daley Thompson, the two-time Olympic champion, was fourth.

Schenk will keep his gold medal with the statute of limitations having expired, although the International Olympic Committee (IOC) welcomed his confession.

"According to our statute of limitations, the IOC in this case - as in similar cases - will not follow up," an IOC spokesman told the German Press Agency.

"We welcome the admission and hope it will help clarify the situation and strengthen the fight against doping.

“At the same time, we hope that Schenk's findings contribute to his own 'well-being' and wish him all the best to cope with his health problems."

Schenk also won the European title in 1990 and won bronze at the World Championships in 1991.

The 53-year-old reportedly reflects upon the health problems caused by the substances in the book.

East Germany is widely believed to have run a state-sponsored doping scheme.