Lobby group Progressive Rugby has branded Ugo Monye's comments that it is "impossible" to return from a concussion too quickly as "unacceptable".
Monye was speaking on BT Sport's Rugby Tonight about how to make the sport safer and avoid head collisions in general, saying: "I think we're good at recognising concussion. I think it's important to state that mistakes will be made, absolutely. You've got people on the pitch and people sat in the stands who are watching it on replay.
"In terms of returning too quickly, that's impossible. There is a clear framework and guideline which is used. You can't even start until you're cleared of a headache and then it's a graduated return to play."