Sir Bradley Wiggins and Team Sky are being investigated by UK Anti-Doping because of a medical package that was delivered to Sky officials ahead of the 2011 Tour de France.

They are expected to question Wiggins, Sir Dave Brailsford and the Sky medical team as part of a wide-ranging probe into an 'allegation of wrongdoing'. Specifically, they will seek answers about a package that was flown to Geneva and then driven to a Team Sky medical official.

Wiggins — who, like Team Sky, denies any wrongdoing — has been under fire since Russian hackers revealed that the first Briton to win the Tour had applied for a Therapeutic Use Exemption (TUE) to use a powerful steroid before his last three major road races.

Sir Bradley Wiggins poses for a photograph at the Rio Olympic Park in the summer

Wiggins celebrates securing victory in the men's team pursuit qualifying round in Rio

Wiggins punches the air after victory in the Tour de France on July 21, 2012

The first was dated June 29, 2011, with the second just days before the 2012 Tour he went on to win.

But responding to questions from Sportsmail, officials at British Cycling confirmed on Thursday that a member of their coaching staff had, indeed, travelled to La Toussuire in France with medication requested by Team Sky on June 12, 2011. On that day, Wiggins celebrated winning the seven-stage Dauphine Libere road race.

While British Cycling have confirmed it was medication for a Team Sky rider, they have not identified the substance nor the rider, citing patient-doctor confidentiality. They have, however, suggested the package did not contain triamcinolone, the drug at the centre of the Wiggins TUE controversy.

UKAD is investigating an allegation of wrongdoing in cycling. In order to protect the integrity of the investigation we will not comment further. UK Anti-Doping statement

They have been unable to confirm if they have a record of what the medication was instead.

At the time Simon Cope, a former rider and now boss of Wiggins' own racing team, was a women's cycling coach at British Cycling.

But at the request of Team Sky he flew to Geneva that day with the medication before hiring a car and completing the final two hours of his journey to La Toussuire. Having delivered the package, he returned immediately to the UK.

Sportsmail understands doping chiefs are investigating allegations centred around the package and whether it was requested by Team Sky doctor Richard Freeman for Wiggins.

The Team Sky cyclist was interviewed on BBC's Andrew Marr Show on September 25

Wiggins (centre) stands on top of the podium at the end of the Dauphine Libere in 2011

In a statement, they confirmed: 'UKAD is investigating an allegation of wrongdoing in cycling. In order to protect the integrity of the investigation we will not comment further.'

Wiggins, Team Sky and Dr Freeman's employers at British Cycling have been asked by Sportsmail about the package and whether the five-time Olympic champion had a private session with Freeman at the back of the Team Sky bus after the final stage of the Dauphine Libere on June 12, 2011.

All three parties refused to respond to the questions on Thursday, although in an email last month Wiggins denied he had an injection that would have required a TUE after the race that day.

Team Sky principal Brailsford said that a meeting between Dr Freeman and Wiggins could not have taken place on the team bus on June 12 because it had left with other riders before their team leader had completed his podium, media and drug-test commitments.

Wiggins (right) is pictured in conversation with Sir Dave Brailsford (left) and Mark Cavendish

Team Sky doctor Richard Freeman (left) and Simon Cope - sports director of Team Wiggins

Wiggins celebrates winning the London 2012 Olympic time trial

However, Sportsmail sought further explanation after a video emerged showing Wiggins outside the bus after the race.

An alternative reason was also initially given for Cope's trip. It was said that he had travelled to the French ski resort to see Emma Pooley, even though the Olympic silver medallist was almost 700 miles away racing in Spain.

Pooley has confirmed she did not meet Cope in France.

In a statement released on Friday,Team Sky said: 'Team Sky was contacted by the Daily Mail regarding an allegation of wrongdoing.

'We take any issues such as this very seriously and immediately conducted an internal review to establish the facts. We are confident there has been no wrongdoing.

'We informed British Cycling of the allegation and asked them to contact UKAD, who we will continue to liaise with.

'Team Sky is committed to clean competition. Our position on anti-doping is well known and we 100 per cent stand by that.'

In the wake of the leaked Wiggins TUE documents that were published by the Russian hackers, the Fancy Bears, a number of well-known figures in cycling have questioned Wiggins's use of triamcinolone before the 2011 and 2012 Tours and the 2013 Giro d'Italia.

Wiggins has denied any wrongdoing, insisting he needed a drug banned in competition to combat asthma and allergy issues.