Australian champion Paralympic track cyclist Michael Gallagher has tested positive for EPO and will miss the Rio Games, the Australian Anti-Doping Authority (ASADA) has confirmed.
The 37-year-old failed an out-of-competition test at a training camp in July, landing him with a mandatory provisional suspension.
ASADA is to investigate the finding, but the organisation said Gallagher - who was born in Scotland - would not be permitted to compete in Brazil, with the Games beginning on Wednesday.
Gallagher won gold in the individual pursuit LC1 class at Beijing 2008, and again in the C5 class four years ago in London.
Widespread doping violations led to Russia receiving a blanket ban from this year's Paralympics.