Constitution Hill was reported by Nicky Henderson to be looking “alert and bright” on Thursday morning – but until the champion hurdler is scoped again on Friday his participation at Cheltenham is no clearer.

The racing world was rocked on Tuesday, when the unbeaten seven-year-old went to Kempton for a routine pre-Cheltenham gallop but was effectively pulled up by Nico de Boinville.

It transpired after he was scoped that he had mucus in his lungs, and Henderson faces a race against time to get his stable star back to full health for a week on Tuesday.

“He can’t stay in his box, if we’ve got any pretentions of running in the Champion Hurdle, you can’t just knock it off and tuck him in bed,” Henderson told Sky Sports Racing.

“We’ve got to find the right balance between keeping him moving but not stressing him in any way at all. He is the most relaxed person you’ll ever come across and I actually think he looks quite bright.

“His coat looks bright and he’s the same as he is every day, he’s no different than he is on a normal morning because he’s just very laid back about life. But at least he’s got the brains to tell us when he’s wrong he is wrong and it is the first time he’s had to do that.

“He looks alert and bright, but he obviously wasn’t feeling well as the work was so sub-par it wasn’t true.

“The plan is to scope him again on Friday. His blood was taken this morning and it will be interesting to see what that says.

“It will be very interesting what comes out tomorrow to see what the mucus level is.

“Horses often get these problems, they are like kids in school. He hasn’t coughed at all. It’s exactly like a school, you can’t have 100 per cent of them right all of the time, it’s not possible. Normally we’d have time to get over it, it’s the timing that is wrong.

“If he was a normal horse you’d leave off him for a week and aim at something else but while there is something else to aim at, there’s only one Champion Hurdle.

“You’d have to be 100 per cent for a race like that. I’ve heard people say he’s got so much in hand it won’t matter but he hasn’t got anything in hand, we all know it’s going to be tough, Champion Hurdles are tough naturally.

“They have to put an enormous amount in and I think the thing with horses as good as him is they can put 110 per cent in, maybe a lot of horses can’t. You can’t go in half-cooked.

“Work-wise he’s done all his galloping, we’d do another piece of work next week to see where he is if everything is testing good. That would have to be him at his best.”