Hughie Morrison has expressed his disappointment after Constitution Hill was ruled out of the Unibet Champion Hurdle, despite his absence elevating Not So Sleepy to become the leading British contender for the Cheltenham Festival’s opening day feature.

Hopes of National Hunt’s flagship horse making the start line were dashed on Monday when Nicky Henderson announced blood test results showed the defending champion had not recovered sufficiently enough from a respiratory infection to line up in the Cotswolds.

That leaves the 12-year-old Not So Sleepy to fly the flag for the home team as he makes his fifth appearance in the Champion Hurdle – having previously finished no better than fifth.

He heads to Prestbury Park in rude health, having claimed the rearranged Fighting Fifth when last sighted.

But far from seeing Constitution Hill’s absence as a positive in Not So Sleepy’s claims for big-race glory, Morrison is regretful that the Seven Barrows superstar will be sitting on the sidelines during the biggest week of the season.

“I’m actually quite disappointed Constitution Hill is not turning up,” said Morrison.

“I don’t think I should be excited really and I’m quite disappointed. At the end of the day, we want the best to be there and the best probably isn’t going to be there. We would have liked to have taken him on – you always want to take on the best.

“Let’s hope we now get there in one piece.”

With Constitution Hill out of the picture and State Man now the heavy odds-on favourite with the layers, it is Not So Sleepy who is the shortest-priced British-trained Champion Hurdle contender, with the veteran a 14-1 chance with Paddy Power.

However, Morrison is still processing his charge’s position in the reformed market and is more worried about seeing some rain appear in the weather forecasts ahead of his big date on Tuesday week.

“I hadn’t really thought of it that way, but I’m just delighted to have something with good reason to be going there really,” said Morrison, when asked about the responsibility of being Britain’s number one hope.

“On his day, he’s a really good horse and he deserves to be there – on a good day, he should be in the money. Over the years, he has run four times in the Champion Hurdle and has run reasonably well, but I’ve always thought I could have had him better.

“We are there to do our best and we’re slightly concerned about the weather forecast looking dry all week, but hopefully the rain will reappear at the weekend for us.

“Racehorses always give you sleepless nights, especially when they are 12 and they have got a few miles on the clock. There is always something creeping round the corner, as Nicky Henderson knows.

“Hopefully we can get him there in good nick but I would like a bit of rain to give us a chance.”