Boss Warren Gatland had been hoping to field his all British & Irish Lions front row of Rees with props Adam Jones and Gethin Jenkins, but the latter should make the plane despite injury worries of their own.

Flanker Sam Warburton – impressive in both matches against England – is in pole position to retain the captaincy while Ospreys’ Richard Hibbard, himself an injury victim, comes into the squad alongside fellow hookers Huw Bennett, Lloyd Burns and Ken Owens.

"The safety and longevity of Matthew's career is paramount," said Wales’ medical performance manager Prav Mathema.

"We are all very disappointed that Matthew will not be with us in the World Cup but his health is at the fore of our decision.

"Following a series of injections and intensive treatment and rehabilitation, the decision has been made to omit him from the squad to allow him to undergo surgery.

"The medical teams of both the Scarlets and the WRU concluded unanimously to proceed with surgery."

Defence coach Shaun Edwards was quick to play down his disappointment in light of Rees’s suffering.

He said: "We have not had our Lions front-row together since the South Africa tour of 2009.

“From a rugby point of view, it is incredibly disappointing to lose your captain and we are gutted he is not leading us to the World Cup.

"There are more important things in life than rugby. And Matthew is in such pain it has to be second to his life.

"We are gutted he will not lead us into the World Cup but he has to take the doctor's advice because you can't live like that.

"He can't sleep and is in constant agony."