The participation of Constitution Hill in this year’s Champion Hurdle is suddenly up in the air after a marked market drift on Tuesday morning which saw State Man go favourite for first Championship race of the week.

Last year’s Champion Hurdle winner scoped dirty after his morning gallop at Kempton racecourse this morning where he trailed home behind stablemates Sir Gino and First Street.

Trainer Nicky Henderson reported that there was “evidence of mucus” in a subsequent scope and that scope will now be analysed before a decision on the Festival is made, which is now within a fortnight’s time.

Henderson said on Tuesday: “We’ve just scoped him. Jamie Knapp, the vet here, has had a look at him. He’s fine. I’ve got a sample here which I’m now going to take to our vet to have it analysed. There is evidence of mucus in there. Nothing else.

“We had a period in January when he had much the same sort of thing. That’s why he couldn’t run in the Unibet Hurdle. It seems that it might have come back to haunt us. We’ll have an answer this afternoon, we’ll see what the figures are. If it is just mucus, you can clear it up with antibiotics.

“His work’s been done. The fact he didn’t gallop all over them doesn’t mean he hasn’t done any work, he’s had a gallop today. He worked at home on Friday. He was scoped last week and was perfectly all right.”

He added: “Of course you’re worried, you’d be crazy not to be. Something’s gone wrong, obviously. He stopped rather like a horse that had bled, but thankfully he hasn’t bled. But Jamie said there is significant mucus.

“By the time he gets home, we can have antibiotics ready and waiting. Jamie says you can knock this on the head within a week, if you’re lucky.

Constitution Hill has been put back in as 1-2 joint-favourite with State Man after the market reformed on Tuesday afternoon.