Sir Clive Woodward believes Wales could win the 2015 World Cup.
Woodward, who guided England to the 2003 World Cup in Australia, believes Wales are genuine contenders if they keep their star men fit.
But he does not believe England are capable of emerging victorious on home soil unless the back division starts to fire.
Wales fielded 10 of the starting XV in the British & Irish Lions' final Test in Australia earlier this month, and Woodward says that statistic shows how strong they are.
"If Wales field their first XV, they are potential World Cup winners," Woodward told Wales Online.
"Wales have not got the depth of options available to England, but they do have the quality. When they are at their strongest, they are a match for any team in the world.
"Their players were crucial to the Lions and I thought skipper Sam Warburton was amazing."
Wales will face tournament hosts England in the pool stages in 2015. And Woodward believes that will be more of a concern for England coach Stuart Lancaster than his Wales counterpart Warren Gatland.
"Stuart is doing an excellent job and has a good team developing," he said.
"And the Lions experiences this summer of coaches Andy Farrell and Graham Rowntree will benefit them hugely.
"But the World Cup will be incredibly competitive in the qualifying pools, particularly for England who are drawn with Wales and Australia.
"It's no longer about development, it's now about results. The England forwards look very impressive but it's time for our backline to step up and start firing on all cylinders."
Should Warren Gatland coach the Lions on the tour to New Zealand in 2017?
Yes, he has earned his stripes
No, there are better coaches in world rugby
No, the coach must come from the Home Nations