A knee injury has put paid to the Rugby career of Wasps and England flanker Tom Rees, the player's club announced on Monday.
The 27-year-old back-rower, who won 15 England caps after making his debut during the 2007 Six Nations, sustained the injury during a pre-season game last summer.
He underwent extensive treatment but has subsequently taken medical advice to stop playing.
"I'm gutted that I have been forced to retire at a time when I feel I could have contributed so much more to my club," Rees said on his club's website.
"Whilst I will always think what might have been, I will also look back on my career and what I achieved with a great deal of pride.
"I would especially like to thank everyone at London Wasps, they have given me such tremendous support at all times through my career but particularly of late, and I am sorry that I won't get to repay them for that."