The Swiss Sport Integrity Foundation confirmed last month that Flückiger was being investigated "for a potential anti-doping rule violation" and had been provisionally suspended, but did not offer any more information.

The suspension meant that Flückiger missed the European Championships.

The Swiss rider has now hit back, denying in a statement that he had "knowingly" taken zeranol and claiming the amount detected in his sample was 0.3 nanograms per millilitre, a figure that is below the 5ng/mL threshold the World Anti-Doping Agency (WADA) requires for it to be regarded as an adverse analytical finding.

WADA guidance is that a concentration of zeranol or its metabolites at less than 5ng/mL being found in a sample should be treated as an atypical finding, triggering a mandatory investigation.

Flückiger has suggested WADA guidance was not followed, although the original Swiss Sport Integrity Foundation statement never said the rider had tested positive.

Ernst König, the director of Swiss Sport Integrity Foundation, denied Flückiger's allegations, speaking to SRF.

Flückiger has also said he returned two negative doping tests shortly before and after the June 5 test in question and is requesting documentation regarding that test.

A hair analysis has been commissioned, but a B-sample test is yet to be requested.

Zeranol, which is typically used as a veterinary drug as it can promote livestock growth, is banned at all times by the World Anti-Doping Code.

It has been found to have been consumed in contaminated meat in the past.