Champion New Zealand horseman Jock Paget faces a lengthy ban and the loss of his Burghley eventing title after the B sample from his horse Clifton Promise returned a positive test for a banned substance.
Clifton Promise was tested after Burghley in September and last month returned a positive reading for Reserpine in his blood. It is a sedative often used to help horses recover from long term injury or illness.
With the B sample checked and the same substance found, Paget now has three weeks to prepare a dossier of evidence before appearing in front of an International Equestrian Federation tribunal.
The whole process could take about six weeks.
Equestrian Sports New Zealand said it had received notification from the International Equestrian Paget said that while the B sample result was disappointing, it was expected as the blood in the B sample was taken at the same time as the A sample.