UK Anti-Doping (Ukad) claimed its 'jiffy-bag' investigation had been "hindered" and may have even been "potentially compromised" by British Cycling's failure to report doping allegations sooner, the BBC can reveal.

In a confidential and highly critical letter dated 14 November 2017, and sent after Ukad halted its inquiry into a mystery 2011 medical delivery, British Cycling was told its medical storeroom at the National Velodrome had been "chaotic and disorganised".

The agency also pointed to "little if any evidence of supervision or executive oversight" of team doctors.

Ukad had refused to release letters it sent to both British Cycling and Team Sky, despite Freedom of Information requests from the BBC and other media organisations, saying it would leave it open to legal action and that it was not in the public interest.

But for the first time, the details can now be disclosed.

Background

Ukad - which is publicly funded - spent 14 months looking into an allegation that a mystery medical delivery for former Team Sky star rider Sir Bradley Wiggins at a race in France in June 2011 contained a banned corticosteroid.

Former British Cycling chief medic Dr Richard Freeman, who administered the substance, along with Wiggins and Team Sky, always denied any wrongdoing, and claimed the package contained a legal decongestant.

However, a lack of documentation about the drug dispatched from the medical storeroom that Team Sky shared with British Cycling at their Manchester headquarters meant Ukad was then forced to bring its investigation to a close with no charges brought.

Freeman said he had lost his records when his laptop was stolen on holiday, and he then failed to talk to Ukad because of ill health.

Wiggins suggested he may sue Ukad, saying he and his family had been put through "a living hell".