Mag & Canyon remain in World Hurdle mix Willie Mullins has left Champion Hurdle contender Nichols Canyon and Mares' Hurdle favourite Vroum Vroum Mag in the Ryanair World Hurdle at Cheltenham on Thursday. However, the champion trainer has removed Annie Power, who has been supplemented for the Champion Hurdle and heads that market. Alpha Des Obeaux, Lieutenant Colonel, Prince Of Scars and Martello Tower are other World Hurdle possibles from Ireland at the six-day stage, while hot favourite Thistlecrack and last year's winner Cole Harden are also among 18 horses still in contention . The Colin Tizzard-trained Thistlecrack has carried all before him in the staying hurdle division this season, landing the Long Distance Hurdle at Newbury and the Long Walk at Ascot before romping home in the Cleeve Hurdle at Cheltenham in January. Cole Harden was beaten by Thistlecrack at Newbury and finished well-held in the Relkeel Hurdle at Cheltenham on New Year's Day, but connections are adamant he will put up a staunch defence of his crown on the drying ground on his return to Prestbury Park next week. Other contenders include the Paul Nicholls-trained duo of Saphir Du Rheu, runner-up last year, and Aux Ptits Soins, and Nicky Henderson's Whisper.