A group of Olympic hopefuls have had their dreams dashed after the eleventh hour reversal of a quarantine exemption.

Twelve Victorian swimmers who qualified for the Olympic trials in South Australia, which begin tomorrow, were granted cross-border permit exemptions to shorten the length of their quarantine period in Adelaide, so they could attend the trials.

But the South Australian government yesterday revoked that exemption.

It means the swimmers, who are in five-day quarantine in South Australia, must now quarantine for 14 days, and will be in quarantine during the trials.

Tim Car and his 20-year-old son, Jackson, who is one of the affected swimmers, are about to return home to Melbourne.

“We’re about to jump on a plane,” he told Neil Mitchell.

“The window has definitely closed.”

Press PLAY below to hear how Olympic hopeful Jackson Car is coping with the devastating news