Trainer-jockey Johnny Murtagh will decide in the next 48 hours whether to let star stayer Royal Diamond make the trip to Australia for November's Melbourne Cup.

Last year's Irish St Leger hero has enjoyed another fine campaign, registering a couple of victories, but ran a disappointing fifth when defending his Leger crown at the Curragh earlier this month.

Due to the expense involved in making the trip Down Under, Murtagh wants to be sure his seven-year-old is in prime condition before booking his place on the plane.

"We have to make a decision before Tuesday. We gave him a nice easy bit (of work) on Saturday morning and we're happy with him, but we want to see if he's really bouncing over the next couple of days," said Murtagh.

"I would have loved if he'd ran a bit better in the Irish St Leger. For some reason he ran a bit flat and I would have loved to see him running a little bit better and really putting himself in line for Melbourne.

"It's a difficult decision. It's a long way to go and costs a bit of money.

"I believe Royal Diamond, on his day, would have a chance of running a very good race in the Melbourne Cup, but we haven't decided yet.

"I think there and back it costs £50,000 plus (to travel), but if you finish in the first 10 (in the Melbourne Cup) you're going to pay for your expenses."

Murtagh has also been associated with another Irish-trained Melbourne Cup hope in Willie Mullins' Simenon, who has already made the trip to Australia.

Murtagh has partnered the six-year-old on each of his three starts this year, but even if Royal Diamond does not run, he will not be on board Simenon in Melbourne.

"I think he's only got 53.5 kilos, so it's a light weight," said Murtagh.

"I spoke to Willie the other day and when he told me the weight, it takes me out of the equation."