Cazoo Derby favourite Luxembourg has met with a slight setback, putting his participation at Epsom into some doubt.

Unbeaten at two, he made a pleasing reappearance just last weekend in the 2000 Guineas when third to Coroebus after stumbling shortly after coming out of the stalls.

Aidan O’Brien, who won both Derby trials at Chester this week with Changingoftheguard and Star Of India, and fields likely types at Lingfield and Leopardstown this weekend in United Nations and Stone Age, will be keeping his fingers crossed the Camelot colt makes a quick recovery.

He said on Friday afternoon: “Luxembourg was just a little bit lame on his off-hind this morning after cantering.

“We’re not sure why just yet, but wanted to let people know with the Derby coming soon.

“In a couple of days we’ll hopefully know a bit more and will issue a further update.”

In the wake of the Luxembourg news, Changingoftheguard has been shortened to 6-1 from 10-1 for Epsom by Coral. Walk Of Stars, who runs at Lingfield on Saturday, and Ballysax winner Piz Badile have both cut to 7-1 from 10-1.

“This latest setback clearly shadows doubts about Luxembourg’s Derby participation. Changingoftheguard proved he could be a big player for the British Classic when he prevailed at Chester, and he is now much closer in the betting with his stablemate,” said Coral’s John Hill.

“Those who have backed Luxembourg for the Derby will be hoping this is a minor setback and that he gets to Epsom in 100 per cent condition. However, this news is enough for us to push his odds out in the betting.”