Top Irish show jumper Cian O'Connor has been stripped of victory at a Grand Prix event in Mexico after his horse Pegasus tested positive for a prohibited substance.

O’Connor and Pegasus had topped the podium at the CSI2 Grand Prix in San Miguel de Allende on October 12th, but a subsequent sample revealed the presence of dexamethasone. The finding placed O’Connor on the International Equestrian Federation’s fast-track sanctions list earlier this week.