Nicky Henderson expects a second blood test on Monday to be the “acid test” in Constitution Hill’s race against time to be fit for the Cheltenham Festival.

The unbeaten and defending Champion Hurdle hero worked poorly at Kempton Park on Tuesday, putting his participation at the showpiece meeting in major doubt.

A scope showed mucus in his lungs and despite slightly more positive news in the following days, results of a blood test on Thursday proved to be another blow.

In a statement issued on X on Friday, Henderson revealed the results of a second scope were more encouraging, but admits his stable star is still “unwell” with his intended return to action in the Cotswolds a little over a week away.

Henderson said: “On what was about as foul and filthy morning as you can imagine at Seven Barrows, Constitution Hill had a light exercise and was rescoped afterwards as planned. This showed the Neutrophil percentage, indicative of infection, was back to normal parameters with no mucus evident.

“This is obviously positive news but we cannot hide behind yesterday’s blood test which basically reveals that, in simple terms, our horse is ‘unwell’.

“He will have a quiet weekend and we propose, as originally planned, to take a further blood test on Monday which I believe will be the acid test. Therefore I think we might leave it until then to keep everybody updated on the situation.”