The head of international cycling tonight responded to increasing pressure on his position by accusing the man at the top of the World Anti-Doping Agency (WADA) of "blatant and aggressive" untruths.
The International Cycling Union (UCI) has been plunged into fresh controversy for disbanding its own inquiry into the Lance Armstrong drugs scandal.
The UCI's Irish president Pat McQuaid has been personally criticised but he hit back tonight by accusing WADA president John Fahey of having a "personal vendetta" against cycling.
"I would therefore urge the president of WADA one more time to try to set his personal vendetta and crusade against cycling aside and to support the UCI in doing what is right for cycling" - UCI chief Pat McQuaid
McQuaid said: "I am very saddened that it has come to this, but I cannot allow the latest blatant and aggressive misrepresentations contained in WADA's most recent press release to go unchallenged.
"Mr Fahey is saying one thing in public and quite the opposite in correspondence with me.
"The UCI is perplexed that WADA has now chosen to rebuff and attack the UCI's willingness to establish a truth and reconciliation commission, having just demanded that the UCI establish exactly such a commission.
"We have now reached this sorry juncture because WADA publicly questioned the independence of the independent commission.
"I would therefore urge the president of WADA one more time to try to set his personal vendetta and crusade against cycling aside and to support the UCI in doing what is right for cycling. Our aims are the same: to rid cycling and indeed all sports of the scourge of doping."
The UCI's decision to terminate the independent commission - whose members include Baroness Tanni Grey-Thompson - followed weeks of wrangling with WADA over its powers and whether those who testified could receive an amnesty.
The central issue of the inquiry concerned two donations by disgraced drugs cheat Armstrong to the governing body, and whether there was any complicity by the UCI in covering up his doping.
The UCI yesterday announced it was scrapping the inquiry in favour of a 'truth and reconciliation' process. McQuaid claimed WADA had agreed to this - something denied by the agency.
Fahey said: "The UCI has again chosen to ignore its responsibility to the sport of cycling in completing such an inquiry and has determined to apparently deflect responsibility for the doping problem in its sport to others.
"UCI has publicly announced that WADA has agreed to work with it on some form of truth and reconciliation. This is not only wrong in content and process, but again deceitful.
"WADA has not and will not consider partaking in any venture with UCI while this unilateral and arrogant attitude continues."
A statement from the commission also pointed the finger at McQuaid.
It said: "Pat McQuaid stated that the UCI 'will co-operate fully with the commission'... and urged all other interested stakeholders to do the same. Neither the UCI nor interested stakeholders have provided sufficient co-operation to enable the commission to do its job. This failure to cooperate makes our task impossible."
The pressure group Change Cycling Now (CCN) has also weighed in and called for the UCI's leadership including McQuaid to be removed.
Grey-Thompson attempted to stay out of the row but called on the UCI to disclose all the evidence.
She said: "It is essential that the final process addresses the accusations against the UCI that the independent commission was first appointed to investigate, and which have now been placed indefinitely on hold.
"Confidence in the integrity of the UCI is vital for the sport of cycling. It is essential that they make full disclosure of all documentation and evidence to allow the sport to move on and regain its standing and reputation."