Anti-doping investigators have swooped on the home of British cycling over doping allegations

UK anti-doping chiefs swooped on British Cycling’s ‘Medal Factory’ HQ on Friday as the crisis which has engulfed the sport reached the home of the national governing body, which it shares with Team Sky.

Two UKAD officials on Friday travelled to the Manchester Velodrome, where the successes of the last three Olympic Games were made.

UKAD would not comment further to "protect the integrity of the investigation" and refused to disclose whether the meeting was pre-arranged or the result of an unannounced visit.

UKAD are at British Cycling and Team Sky’s base in Manchester to carry out the investigation

British Cycling and Team Sky is cooperating with UKAD’s investigation into "allegations of wrongdoing within cycling".

On Thursday evening it was just a single claim being investigated, but now there is more than one.

The initial UKAD announcement came as the Daily Mail reported the anti-doping authority is investigating Team Sky and Sir Bradley Wiggins over the contents of a medical package, allegedly delivered to Team Sky in France on June 12, 2011.

Mirror Sport understands Wiggins and his representatives have received no notification from UKAD and believe the 36-year-old is not a subject of the investigation.

It has been reported that Sir Bradley Wiggins is under investigation but the 2012 Tour de France winner says he has not been notified

Five-time Olympic champion Wiggins, Britain’s first Tour de France winner in 2012, said in a statement to on Saturday: "I welcome this investigation."

Team Sky are "confident there has been no wrongdoing" and had asked British Cycling to contact UKAD.

British Cycling said it is "cooperating fully".

David Brailsford, performance director of British Cycling and general manager of Team Sky

There is no timescale for UKAD investigations. And UKAD did not go into any detail about the allegations and mentioned no names.

But concerns on Thursday were raised about the availability of controversial and powerful painkiller Tramadol among the Great Britain team at the 2012 Road Cycling World Championships.

Tramadol is on the World Anti-Doping Agency’s monitoring list, with concerns over its side effects.