Leading British bookmakers have announced that they will refund hundreds of thousands of dollars of bets placed on some of the Godolphin horses which tested positive for banned steroids.
Ladbrokes said it had refunded £200,000 ($305,000) of ante post stakes on horses in the care of Classic-winning Godolphin trainer Mahmood Al Zarooni owing to "exceptional circumstances".
The horses concerned were the unbeaten filly Certify, Desert Blossom, Artigiano and Restraint of Trade.
In Twitter announcements, William Hill also followed suit while Paddy Power said that it would refund punters who had backed Certify for the 1000 Guineas, which is run at Newmarket at the end of next week.
Dubai-based Godolphin is under a cloud after it was revealed 11 of their horses had tested positive for anabolic steroids.
Godolphin, the brainchild of Dubai ruler Sheikh Mohammed, said an urgent review would be carried out.
All 11 horses who tested positive came from Mahmood Al Zarooni's yard in Newmarket, England.
The trainer - who has made a big impact since becoming one of Godolphin's trainers winning last year's Dubai World Cup and the oldest classic the English St Leger - said he had made a catastrophic mistake.
Godolphin was founded in 1992 and has recorded over 2,000 wins - including 200 Group One victories - in 14 countries.
Godolphin racing manager Simon Crisford said: "This is a dark day for Godolphin. We are all shocked by what has happened.
"His Highness Sheikh Mohammed was absolutely appalled when he was told and this is completely unacceptable to him.
"Sheikh Mohammed has instructed me to begin an urgent review of all of our procedures and controls. That is already under way and we will take advice from the BHA in completing it."