As a Times investigation has revealed, Ineos tested their riders using carbon monoxide on February 1 this year, employing a method the UCI, cycling's international governing body, has indicated would now be prohibited under rules announced on the same day, which came into effect from February 10. The new rule says that only a single inhalation of the gas is allowed, two weeks apart. Tests conducted for Ineos on February 1 involved two inhalations, lasting five or six minutes, 15 to 20 minutes apart.

The new rules also specify where such tests for measuring haemoglobin mass, which in turn can determine the impact of altitude training, can be conducted.

"The new regulation forbids the possession, outside a medical facility, of commercially available CO rebreathing systems connected to oxygen and CO cylinders," the regulation states. "This ban applies to all licence holders, teams and/or bodies subject to the UCI regulations and to anyone else who might possess such equipment on behalf of riders or teams."

The regulation adds that "the inhalation of CO will remain authorised within a medical facility".

Team Ineos were staying at the SyncroSfera sport hotel near Denia in Spain. It has a physiotherapy centre and boasts altitude simulation rooms.

But Alexander Kolobnev, the Russian former professional cyclist who founded the hotel, said he was unaware that riders had been tested in room 101 and said his hotel did not hold the appropriate certification for such tests.

"The statement that 'carbon rebreather testing has been conducted at our hotel' is incorrect," Kolobnev wrote in an email. "SyncroSfera is a sports, wellness and performance centre with advanced facilities for training, recovery and physiotherapy, eg altitude simulation, hyperbaric therapy, rehab. We have never offered or performed any activity related to carbon rebreathers as a hotel service.

"Regarding UCI rules, we are aware that any procedures involving carbon monoxide rebreathers are to be conducted in certified medical environments under medical supervision. We do not operate as a hospital or medical testing laboratory for such procedures."

In a further telephone conversation on Monday, The Times pointed out that it is detailed in an official Ineos itinerary that seven riders were listed for "Hb mass testing" in "room 101" of his hotel on January 31 and February 1.

He confirmed that room 101 is an "absolutely normal bedroom" at the very end of a corridor, adding: "I know nothing about this. We are not a medical facility."

Ineos and the hotel have not broken any rules because the new regulations -- which were prompted by reports during the 2024 Tour de France that professional teams were using carbon monoxide rebreathers amid concerns that repeated inhalations of the potentially deadly gas could also be used to boost athletic performance -- did not apply until nine days after they conducted their tests.

From that date the UCI has also required that "any CO inhalation for the purpose of determining total Hb mass must be recorded in the medical file established for each athlete".

But it was actually the previous November that the UCI issued a release urging teams to follow certain guidelines while it worked on a new set of regulations to cover the use of carbon monoxide. "The UCI clearly asks teams and riders not to use repeated CO inhalation," said the organisation in a statement. "Only the medical use of a single inhalation of CO in a controlled medical environment could be acceptable."

Last week Ineos Grenadiers issued a statement insisting they had done nothing wrong. "The UCI made an announcement on this issue over eight months ago, in February, and of course we have been adhering to their rules and regulations," they said.

On Monday The Times asked them for a response to Kolobnev's comments about being unaware that testing had taken place in his hotel, and his insistence that the SyncroSfera is not a medical facility. As yet they have not responded.

Spanish hotel 'knew nothing' about Ineos using room for now-banned tests