Former England head coach Brian Ashton believes that current boss Stuart Lancaster needs to identify a backup to current number 10 Owen Farrell.
Ashton believes that Lancaster's decision not to have a backup specialist number 10 in his squad for the Six Nations should not be replicated when the World Cup comes around.
"We really need to sort out who is the next England number 10 if Owen Farrell breaks his leg," the London Evening Standard quotes Ashton as saying.
"What I am struggling to get my head around, and I like Stuart Lancaster a lot, is why do you develop Billy Twelvetrees as a rounded number 12 and then move him to outside-half if something happens to Farrell? The whole dynamic of the team would change.
"The last thing you want to do is go to a World Cup with a number 10 who doesn't have many games under his belt because, as I know, that tournament is a totally different challenge."
England will take on Ireland on Saturday.