Former Team Sky doctor Richard Freeman has pulled out of a long-awaited appearance before a parliamentary inquiry into doping in sport.
Dr Freeman, who currently works for British Cycling, was scheduled to answer questions on Wednesday about the contents of a medical package he administered to Sir Bradley Wiggins at the Criterium de Dauphine in June 2011.
He has told the Culture, Media and Sport Select Committee he is unwell and cannot attend.
A Committee spokeswoman told Sky News Dr Freeman will be asked to provide written evidence and may be asked to attend at a later date.
UK Anti-Doping has been investigating “an allegation of wrongdoing” in relation to the package for five months.
UKAD’s chief executive Nicole Sapstead and Simon Cope, the former British Cycling women’s team coach who delivered the package to Team Sky, were due to give evidence.
UKAD had planned to provide an update on the status of their investigation prior to the hearing, but will now not make any statement ahead of the hearing.
At an earlier hearing, Team Sky principal Sir Dave Brailsford told the committee the package contained the legal decongestant Fluimicil, which was administered via a nebuliser.