Former Australia coach Eddie Jones has said that England have a weakness at half-back which means they will not win the Rugby World Cup.
"I don't think Ben Youngs is a Test half-back," Jones told BBC Radio 5 live.
"He is good on go-forward ball but when the ball gets slow he struggles to make decisions and I think Toby Flood is the same, which is a big weakness.
"That combination means I don't think they can win the World Cup."
Youngs, who made his Test debut in 2010, has only 12 international caps but impressed when England beat Australia at Twickenham last November, setting up Chris Ashton's length-of-the-field try.
He underwent knee surgery earlier this month but is expected to be fit for the World Cup.
While he does not think they are likely winners, Jones does accept that England have some strengths which mean they will still be challengers at the tournament, which begins in New Zealand on 9 September.
"Their pack will be very strong, their line-out and scrum will be good and they have pace on the wing in Ashton," he added. "They will be competitive because of their forward pack, but that's the case with England at most World Cups.
"Of the other leading sides, the Australian team is based around very young players and South Africa have not gone as far forward as they would have wanted in the last four years.
"New Zealand should win but watching them play I think they are in danger of becoming too complicated for themselves. They play best when they use their athleticism and power."
England, who face Wales in their first World Cup warm-up game at Twickenham on 6 August, played a behind-closed-doors game of 20 minutes each way at the Twickenham Stoop on Thursday.
There was a scare for Courtney Lawes as he suffered a neck injury and was taken to hospital for a precautionary X-ray but the Northampton lock was subsequently given the all-clear.
Saracens wing David Strettle also had to leave the action with a leg injury.
Team manager Martin Johnson said: "It was a good end to the week and the boys enjoyed having a run-out in a different environment.
"Inevitably it was competitive and you wouldn't have it any other way. But to be honest the whole training camp has had that edge that you want from a group of players vying for 30 spots."