Team Sky boss Dave Brailsford has revealed that a mystery package delivered to Bradley Wiggins during the 2011 Criterium du Dauphine contained decongestant Fluimucil.
Brailsford faced a grilling when he appeared before a Culture, Media and Sport Committee on Monday as part of a long-running inquiry conducted by MPs into sport's fight against doping.
He was quizzed, amongst other things, about a medical substance which was delivered by British Cycling coach Simon Cope to Wiggins when he was competing in a race ahead of the Tour de France five years ago.
Brailsford said it was a substance which is used for clearing mucus and is not on the banned list.
"Doctor Freeman [Team Sky doctor Richard] told me that it was Fluimucil that was in the package, a product that is for a nebuliser. That is what was in the package."
Asked why the substance had been flown out to Wiggins when it could have been purchased in France, Brailsford said: "I don't think it was convoluted, I think that this was the easiest possible way.
"The fact of the matter was that Simon Cope was already flying out. What we have on a regular basis, is people moving in and out and when you become aware of people moving in and out then, if you need anything, you can ask people to bring things with them.
"I think that is maybe where the whole situation has been misled is that the sole purpose for Simon Cope at the end of the Dauphine wasn't expressly to bring and deliver a package."
Wiggins and Team Sky have faced questions after details of the five-time Olympic champion being granted therapeutic use exemptions (TUEs), which permitted him to take a banned steroid before major races.
Brailsford defended 2012 Tour de France winner Wiggins once again, but said Team Sky have lessons to be learned at the end of a year which has seen them come under investigation by UK Anti-Doping.
"There are lessons to be learned. I have handled this situation very badly." he said.
"We've a fantastic reputation and our team don't deserve to have this shadow cast over them and it pains me.
"But we have reviewed all our policies and how we use TUEs in the future and how do we gain and provide transparency while protecting competitive advantage. We invite anybody to come and examine us and scrutinise us."