He becomes the third athlete this year - alongside Linford Christie and Doug Walker - to be cleared of using the banned substance.

Disciplinary proceedings against the 400m runner have now been dropped.

Cadogan was suspended after testing positive for metabolites of the substance in an out-of-season test in November 1998.

'Cleared of all charges'

A UK Athletics statement said: "The disciplinary committee concluded that it could not be proven beyond reasonable doubt that the substance present in the sample was derived from a prohibited substance.

"Gary Cadogan has therefore been cleared of all charges."

In response, a statement from the runner said: "The IAAF [International Amateur Athletics Federation] must realise there are too many unexplained cases of so-called nandrolone offences in relation to athletes who would have no cause to take such a drug.

"I myself proved negative two weeks following the alleged positive finding which brought me before this hearing today. That in itself is sufficient evidence for the IAAF to begin to question the accuracy of these tests."

Cadogan has been bitterly critical of "the IAAF's decision to breach confidentiality" that led to his name being published in a list of pending cases in a newsletter released by the federation. He has requested an inquiry.