The New One will miss the bet365 Select Hurdle at Sandown on Saturday due to a dirty scope.
Trainer Nigel-Twiston-Davies had hoped his admirable eight-year-old would have the chance to end the season on a high after falling in the Aintree Hurdle two weeks ago.
However, The New One is not well enough to try to add to his career tally of 16 wins from 25 starts.
"His trachea wash wasn't good enough," said Twiston-Davies.
"We had a look and he's got muck in his lungs, so he's not running.
"He won't run again this season, that's it."
