Constitution Hill has been ruled out of Cheltenham Festival.
The seven-year-old unbeaten hurdler was due to defend his Champion Hurdle crown at next week’s meet but was found to be suffering from an infection when working poorly at Kempton last week.
While the horse showed signs of improvement, blood test results on Monday morning confirmed the need to withdraw from the festival.
Trainer Nicky Henderson said in a statement on Monday: "Very sadly we are going to have to admit defeat in the battle to get Constitution Hill ready for the Champion Hurdle and therefore have to declare that he will not be running there this year.
"He has undoubtedly improved over the weekend and seems noticeably brighter than he was at the end of last week and I really did think he was much perkier when ridden this morning.
"Unfortunately the all-important blood test shows that although the figures have also improved they are quite a way from being satisfactory for a horse to commence serious training and to race in a week's time.
"There are three significant markers on the blood test all of which have down since Thursday's sample but are still raised enough to indicate that he has not fully recovered from whatever was ailing him.
"The only way to continue the improvement is not to stress him and he obviously cannot run in these Olympic Games if he's not trained sufficiently.
"This is very sad for all of us and particularly Michael but it is in everybody's best interests that we ensure we have a fit and healthy Constitution Hill to win back his crown next year.
"As no further bulletins will be required I would just like to say how much we have appreciated everybody's support and messages over the last week."
