The head of UK Anti-Doping has said she is "extremely concerned" about allegations that a doctor sold banned drugs to athletes.
The organisation's chief executive Nicole Sapstead told Sky News: "UK Anti-Doping is extremely concerned by the allegations made in the Sunday Times.
"We will be investigating fully those allegations but we’re now the subject of an independent review and it would be deeply inappropriate for me to say anything further at this time."
Her words come a day after the newspaper's undercover investigation alleged that doctor Mark Bonar, 38, was charging stars thousands of pounds for performance-enhancing drug programmes.
He allegedly prescribed banned drugs - including erythropoietin (EPO), steroids and human growth hormone - to 150 sportsmen, including Premier League footballers.
In the meetings, the doctor claimed his network of "clients" included a cricketer, cyclists and tennis players.
He also told reporters he had treated Arsenal, Chelsea, Leicester City and Birmingham City players - but the clubs have strongly denied the allegations.
Dr Bonar denied the allegations when they were put to him by the newspaper, later claiming in a series of messages posted on what appears to be his Twitter account that they were "false and very misleading".
Culture Secretary John Whittingdale has called for an urgent inquiry into the sport doping claims, saying he was "shocked and deeply concerned".
Part of the inquiry will focus on the taxpayer-funded UK Anti-Doping (UKAD) watchdog, which was apparently given evidence on the matter two years ago, but failed to take action.
When Sky News asked Ms Sapstead if she welcomed the investigation, she replied: "Yes I do - very much so."
When asked if she had any intention of resigning, she gave no answer.
On Sunday it was reported that UKAD began an investigation into Dr Bonar in 2014 after information supplied by an athlete.
That person went on to supply UKAD with handwritten prescriptions, allegedly issued by Dr Bonar.
But Ms Sapstead said the organisation was unable to act because Dr Bonar was not governed by any sport.
UKAD said the doctor fell outside its jurisdiction and it did not believe there were grounds to refer the case to the GMC.
Sky News Correspondent Enda Brady said: "I'm told by sources inside UKAD that the information passed to them two years ago was simply too sketchy to act on at the time and they told the whistle-blower to go away and come back with stronger evidence.
"So I think the first question will be: why didn't they follow up that initial lead they were given in April 2014?"
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