British sprinter CJ Ujah's B sample from the Tokyo Olympics has tested positive for banned substances, the International Testing Agency (ITA) has announced.
Ujah provided the sample on August 6, the ITA said, the same day that he was part of the British team which won silver in the men's 4x100 metres relay.
The agency said now the B sample had confirmed the result of his A sample, his case had been referred to the Court of Arbitration's Anti-Doping Division (CAS ADD).
The court division will consider the finding of an anti-doping rule violation and the disqualification of the British relay team, the ITA said.
Canada, who came third, are in line to move up to silver and fourth-placed China into the bronze position.