The worst-kept secret in racing was confirmed on Tuesday when trainer John Moore announced Joao Moreira would replace rival Zac Purton on reigning horse of the year Military Attack in next weekend's Group One Citibank Hong Kong Gold Cup.

Purton's association with Military Attack coincided with a string of victories to end last season, capped by an easy win in the Group One Singapore Airlines International Cup, but the Australian had come up winless in four starts this season.

Zac simply wasn't able to deliver the last four times
John Moore

Moreira had been riding the six-year-old in trackwork and yesterday partnered the horse in a barrier trial - after which the change was still unconfirmed by either Moore, Moreira or Purton. But after Moore met with owner Steven Lo Kit-sing last night, he confirmed the switch.

"We knew Joao would be riding him but needed to speak to the owner to make it official, and Steven had been out of the country," Moore said. "Moreira rides my top horses and he is the stable elect in Group One races - when he is available he is my first choice. The owner left it up to the trainer to decide the jockey."

Wide barrier draws or unsuitably short distances, or a combination of both, have certainly hampered Purton in the horse's four runs this preparation - but Moore said it was "time for a change of luck".

"Zac simply wasn't able to deliver the last four times," Moore said.

Purton leads a fast-closing Moreira by nine in the Jockeys' Championship and although losing the ride is another blow to his title chances he gave his blessings to connections.

"The horse is in his best form now, and obviously ready to win, so I wish them well," he said.

Military Attack was joined by four stablemates in a specially convened 1,600m turf trial at Sha Tin on Tuesday, Same World (Weichong Marwing), Dominant (Karis Teetan), Dan Excel (Neil Callan) finishing behind Stewards' Cup winner Blazing Speed (Mirco Demuro).

Each of Moore's horses was partnered by the raceday jockey, except Dominant, who will be ridden by Tommy Berry, pending Jockey Club approval, with Teetan to ride Ashkiyr.

Military Attack finished last in the slowly run heat but was stuck behind horses late.