Johnson says the sport's credibility has gone down the drain

Arbeit, the former head coach of the German Democratic Republic, is suspected of being behind the systematic doping programme in East Germany during the 1980s.

Writing in The Daily Telegraph newspaper, Olympic gold medallist Johnson said Lewis was guilty of "stupidity" for hiring Dr Arbeit and said she was doing more harm than good to the sport of athletics.

"You have to wonder what's going on inside Denise Lewis's head," wrote Johnson.

"I'm afraid that whatever it is, it seems to be contagious. First, Tim Montgomery had it, then Marion Jones caught it, and now Denise has it.

"All three of these prominent, high-profile athletes have hired coaches with confirmed and admitted involvement with steroids."

To think that the reputation of the coach will not be attached to them is another thing altogether: it is called stupidity Michael Johnson Lewis backed over tainted coach

Johnson was equally critical of Montgomery and Jones after they teamed up with Charlie Francis, the disgraced coach of Ben Johnson.

Jones, the Olympic 100m champion, and her boyfriend, the 100m world record holder, subsequently ended their relationship with the Canadian.

But Johnson says athletics has suffered another body blow with the decision of Lewis to join forces with Ekkart, who has claimed that athletes cannot compete for medals unless they take performance-enhancing drugs.

"There is no absolutely no excuse for athletes like Lewis, Jones, and Montgomery to hire coaches who feel that athletes cannot compete without of drugs," wrote Johnson.

"These are all great athletes who I doubt have ever used a performance-enhancing drug. However, once the association with coaches like these starts, every great performance they achieve will be met with scepticism.

Frank knew that Dr Arbeit's involvement would bring a lot of attention Max Jones, UK Athletics' performance director

"And to think that the reputation of the coach will not be attached to them is another thing altogether: it is called stupidity."

According to Max Jones, UK Athletics' performance director, Lewis was made aware of the furore Dr Arbeit's involvement would cause when they met last month.

Jones said he knew about Dr Arbeit's involvement only when he met with Frank Dick, who now guides Lewis, at the World Indoor Championships in Birmingham in March.

Jones, who later met with Lewis to discuss her training programme, said: "Frank knew that Dr Arbeit's involvement would bring a lot of attention and when I met with Denise, I discussed the implications.

"At the end of the day, this was Frank's shout and he clearly thinks Arbeit is the best man for the job."