Cycling's world governing body on Friday roundly rejected claims from the man who brought down Lance Armstrong that they had contributed nothing to the fight against doping in the sport.
The head of the the US Anti-Doping Agency (USADA) Travis Tygart told a French Senate hearing on Thursday that the International Cycling Union (UCI) had blocked efforts to clean up the tarnished sport since the scandal broke last year.
But the UCI responded strongly, saying in a statement on its website uci.ch: "The UCI categorically rejects allegations of collusion... and states categorically that it has nothing to hide".
Giving evidence under oath to a committee from the upper chamber of parliament investigating the fight against doping, Tygart claimed that the UCI 'did everything to put obstacles in our way' over the Armstrong affair.
A devastating USADA report published last October said Armstrong orchestrated what it termed the biggest doping programme in sporting history during his career, sending shockwaves through the sport.
The UCI later rubber-stamped the findings, banned the Texan rider for life and stripped him of his record seven Tour de France wins between 1999 and 2005.
Failure all round
But questions remain about the extent of the governing body's knowledge of his illegal activities, including claims that they were complicit in covering up positive dope tests.
Tygart, whose organisation fought a public battle with the UCI over jurisdiction in the Armstrong case, also criticised the federation's response since their report, accusing them of doing 'absolutely nothing' to crack down on the use of banned substances.
A UCI spokesman accused Tygart of courting headlines and countered that USADA and the World Anti-Doping Agency (WADA) stymied the work of an independent commission it set up to look into historical doping cases.
"No attempt by Travis Tygart to rewrite history will change the fact that USADA failed to catch Lance Armstrong having tested him just 49 times during his career. The UCI by comparison tested Armstrong 189 times"
The commission was disbanded in January after protracted argument about its powers and whether witnesses would be granted an amnesty protecting them from subsequent disciplinary action.
"He should establish the facts before jumping to conclusions," the UCI spokesman said.
"It's all very well Mr Tygart talking about cooperation, but let's not forget that the Independent Commission was only disbanded because of USADA's and WADA's point-blank refusal to cooperate with it.
"Simply, the UCI was left with no choice but to close it down; it made no sense to go forward without the participation of these two bodies.
"One can only assume that their refusal to cooperate with the Independent Commission was due to their fear that their own shortcomings would be exposed.
"After all, USADA and WADA also tested Armstrong over many years and also failed to catch him. It was only with the benefit of the US Federal Investigation that USADA was finally able to gain evidence of Armstrong's doping.
"No attempt by Travis Tygart to rewrite history will change the fact that USADA failed to catch Lance Armstrong having tested him just 49 times during his career. The UCI by comparison tested Armstrong 189 times."
Work by the UCI to catch Armstrong's former team-mates Floyd Landis and Tyler also enabled the investigation against Armstrong, the spokesman said.