It has also been reported that Team Sky doctors attempted unsuccessfully to prevent their star rider Sir Bradley Wiggins from being granted a fourth therapeutic use exemption for an otherwise banned substance.

According to reports published in The Times and The Guardian, a UK Anti-Doping (UKAD) investigation has found evidence suggesting testosterone patches were delivered to Freeman at the National Cycling Centre (NCC) in Manchester six years ago when he was a British Cycling medical official.

Testosterone is a completely banned substance in sport due to its performance enhancing benefits.

Freeman has reportedly told UKAD that the patches had been sent in error and were not for any riders.

Dr Steve Peters, the former head of medical at British Cycling and Team Sky, told the Sunday Times how he and a colleague had questioned Freeman over a package when it arrived but were satisfied that it was "an administrative error".

A wider probe into a "mystery package" delivered for Sir Bradley during the 2011 Criterium du Dauphine is ongoing.

Freeman, a former Team Sky doctor, supposedly received the package on behalf of Sir Bradley on the last day of the traditional build-up race for the Tour de France.

It is claimed that the package contained fluimucil, a decongestant that is used to treat coughs and sore throats, but elements of the story are still unclear.

Freeman also received three TUEs for Sir Bradley to use the corticosteroid triamcinolone to treat pollen allergies before major stage races.

The Sunday Times have reported today that one of Freeman's Team Sky medical colleagues had changed the team's access password to the TUE application website of the World Anti-Doping Agency.

The doctor was reportedly denied a new password when he asked for one three days before the Tour of Britain in 2013.

Freeman had been scheduled to appear in front of a Culture, Media and Sport Select Committee of the UK Parliament last week, but pulled out due to ill health.

A spokesperson for the Committee said it will offer Freeman "the option of supplying written evidence and may call him to appear when he's well enough".

TUEs allow athletes to use otherwise banned substances to treat medical conditions.

There is no suggestion those using them have done anything wrong.