The World Anti-Doping Agency is investigating the UK Anti-Doping (UKAD) agency over claims it allowed British Cycling to carry out its own probe into a rider's sample, which allegedly contained a banned anabolic steroid.
The claims in the Mail on Sunday come just over a week after British Cycling's former chief doctor Richard Freeman was struck off the medical register, after a tribunal found he had ordered the banned steroid testosterone.
The UKAD agency has issued a statement in response to the allegations saying: "We are working with the World Anti-Doping Agency to investigate claims relating to private testing carried out by British Cycling in 2011.
"UKAD is examining archives to confirm decisions that were taken in 2011 followed due process set by WADA."
- Freeman struck off medical register
- Freeman's fitness to practise 'impaired', tribunal rules
- Freeman ordered testosterone for doping, tribunal told
A British rider's sample from an out-of-competition test in late 2010 was reported to have contained irregular levels of nandrolone.
Nandrolone is known as a "threshold substance", where the amount found in a sample needs to be above certain thresholds to trigger action by an anti-doping organisation.
British Cycling has told Sky Sports News they are reviewing their archived records and will "share the findings with the relevant parties".
Rather than UKAD undertaking the investigation itself as dictated by the WADA Code, the agency alerted British Cycling, who conducted its own internal investigation, the reports said.
WADA said in a statement to the Daily Mail that it would contact UKAD for more details.
"Some of the information provided to WADA on this is of significant concern," a WADA spokesperson said.
"We have asked our independent Intelligence and Investigations Department to look into this matter and to contact UKAD to seek further information."
The UKAD spokesperson added: "Sometimes amounts of a 'threshold substance' can be reported by the laboratory in a negative sample which are found to be below the threshold where an investigation is required.
"These are trace amounts and can sometimes occur in the body naturally.
"The guidance from WADA is that these trace findings may be used to help to decide who gets tested and when in the future, but does not automatically lead to an investigation."
A British Cycling spokesperson told Sky Sports News: said: "We are unable to give full comment on this story at this stage as the events took place over 10 years ago and none of the senior management team involved have worked for British Cycling for some time.
"We are reviewing such archived records that exist from this period and, although that is not a straightforward or quick process, we will share the findings with the relevant parties."