Australia's defensive coach John Muggleton believes England's forward pack are too old to win the World Cup.
The former rugby league international said the English pack, which has an average age of 29, would struggle to cope with the heat of Australia.
"I question how much you can teach a 34-year-old and I think England have reached their peak," Muggleton said.
Muggleton, whose defensive patterns played a significant role in Australia's victory at the 1999 World Cup, also predicted England's players would struggle with the hard grounds.
England play their first two pool matches in Perth, where the pitches are notoriously hard.
"Their medical staff's going to be working overtime and their coaching staff's going to have to make some compromises with their training, because of the hard ground," Muggleton said.