England's recalled fly-half Jonny Wilkinson has yet to reach his peak, according to Rugby Football Union elite rugby director Rob Andrew.
Wilkinson impressed in training for England at Twickenham last week
Wilkinson, who played under Andrew at Newcastle, will make his long-awaited return for England in Saturday's Six Nations match against Scotland.
"Jonny is only 27, he hasn't got to the peak of his powers," said Andrew.
"The work he has been doing over the last few years has made him sharper and he is more experienced as a person."
Wilkinson has been picked for the Twickenham contest despite having played only 40 minutes of rugby in 12 weeks.
He came off the bench to play in Newcastle's 39-5 defeat at Leicester on Saturday - his first match since suffering a lacerated kidney against Bristol on 3 November.
Wilkinson has not played for England since the World Cup final in 2003 after suffering a lengthy list of injuries but Andrew says he deserves his recall after a traumatic three years.
You have to ask what this says to Toby Flood and every other aspiring England fly-half
Former England captain
"I probably know Jonny as well as anyone, and the difficult times he has had over the last three years have been very tough on him," Andrew added.
"It is a travesty the guy hasn't played for England since the World Cup final. He has had dark moments, when he thought he might not get the opportunity again.
"But in the last six to 12 months I have seen a different Jonny. I have seen a Jonny who is going to enjoy the rest of his rugby career, whatever that holds for him.
"I always felt he would come back and, if his body gave him a chance to play, he would go on to become a better player."
Despite his lack of rugby, new England head coach Ashton has selected the World Cup winner ahead of his Newcastle team-mate Toby Flood at fly-half.
Johnson and Wilkinson: Key parts of England's World-Cup winning side
And that decision has been supported by former England captain Martin Johnson, who told BBC Sport: "He's a world-class number 10 with more than 50 caps and a wealth of experience.
"It brings confidence and reassurance to the whole squad that you've got a world-class player there.
"It just gives everyone reassurance that you've got a guy who's been involved with winning matches in every Test playing nation in the world," he said.
"He has been there and done it at every level of the game.
"That's not saying that Toby Flood is not an exciting young guy. But he's very young and relatively inexperienced. I think he could go out there and play very well in Test match rugby."
Johnson says the introduction of Wilkinson, along with the presence of other experienced players like Jason Robinson and Phil Vickery, will make England a stronger proposition than they were during the autumn internationals.
"Against the All Blacks we had a guy making his debut at nine (Shaun Perry) and a guy making his debut at 12 who was very young (Anthony Allen).
"It's very difficult to win Test matches in that situation. You can't take all your experienced players out and expect to perform at the highest level."
Another former England captain, Will Carling, said he thought Wilkinson had been brought back too soon.
"I don't want him rushed back," Carling told BBC Sport.
"The pressure on him will be incredible. And you have to ask what this says to Toby Flood and every other aspiring fly-half.
"It's nothing to do with current form - it's his form of nearly four years ago."