Sir Gino, who had been the odds-on favourite for the Arkle Trophy at Cheltenham next month since his brilliant chasing debut at Kempton’s Christmas meeting, has been ruled out for the remainder of the National Hunt season with an infection following a minor leg injury sustained during a routine piece of exercise last week.

Nicky Henderson’s five-year-old beat Ballyburn, one of the top novice hurdlers last season and a Grade One winner over fences since, with ease in December, prompting immediate comparisons with previous Arkle winners from the yard including Sprinter Sacre, Altior and Shishkin.

He missed an intended prep run for Cheltenham in the Game Spirit Chase on Saturday, however, and his price for the Arkle started to drift ominously on the Betfair betting exchange on Monday morning before a statement from Henderson’s stable confirmed the news that his ante-post backers had been dreading.

“Unfortunately, Sir Gino’s situation has deteriorated somewhat and he has been admitted to the equine hospital,” Henderson said in a statement on X. “As a result of initial examinations … an infection has invaded the ligaments in his near-hind leg.

“This will require lengthy treatment that will sadly rule him out of any further racing this season.

“This is a dreadful blow to [Sir Gino’s owners] Joe and Marie Donnelly and everybody at Seven Barrows but we will be doing everything possible to help this incredible bright light back to full fitness next season.”

The news on Monday means that Sir Gino will be denied a run as favourite for a festival Grade One for the second year running, as he was ruled out of the Triumph Hurdle last year a day before the race as Henderson’s string struggled with the effects of a virus at the worst possible moment of the campaign.

In his absence, Majborough was an impressive winner of the Triumph and the same horse has now replaced Sir Gino as odds-on favourite for the Arkle at a top price of 8-13. Next in the betting is L’Eau Du Sud (5-1), the comfortable winner of the Grade Two Kingmaker Chase at Warwick on Saturday, while Mistergif, the winner of his only start over fences to date at Fairyhouse in January in a notably quick time for a chasing debutant, is a 10-1 chance.

If there is a crumb of consolation for Henderson after Monday’s news it is that Sir Gino was ruled out by an injury rather than any hint of a bug in the yard. Overall, in fact, his string appears to be in rude health with just 29 days left to the opening day of the festival, a point that was underlined by the emphatic success of Joyeuse in Saturday’s valuable William Hill Handicap Hurdle at Newbury.

The most successful British trainer at the Cheltenham festival also still has three warm favourites for the meeting next month: Constitution Hill, in the Champion Hurdle on Tuesday’s opening card on 11 March; Jonbon, in the Queen Mother Champion Chase the following afternoon, and Lulamba in the Triumph Hurdle on 14 March.