Warren Gatland has defended the selection of Luke Cowan-Dickie for the British and Irish Lions' opening fixture in South Africa in response to persistent criticism from anti-brain injury campaigners.

Cowan-Dickie appeared off the bench against the Sigma Lions on Saturday, a week after being knocked out in Exeter's Gallagher Premiership final defeat by Harlequins.

Former England scrum-half Kyran Bracken, a member of concussion lobbying group Progressive Rugby, described Cowan-Dickie's selection as a "stain on our great game", as well as condemning the HIA as "not fit for purpose".

The England and Chiefs hooker will make his full Lions debut against the Sharks on Wednesday, and Gatland insists the tourists went above and beyond following the guidelines in place.

"There are strict protocols that our medical team follow that World Rugby have brought in for players to go through," Gatland said.

"We had a world-renowned specialist in concussion look at Luke and he cleared him as well.

"Every player is affected differently. Sometimes a player can be knocked out and recover and be perfect in a very short time.

"Other players might get a very slight knock and it can take them a while to recover from that. There is no similarity in terms of what different players go through with their cases.

"All I can say is that I 100 per cent follow the advice of the medical team. They go through the protocols and when a player is passed fit then he's considered for selection.

"I can tell you there's definitely no pressure from the rugby side. If he's not right then he wouldn't have been selected.

"I don't know how much more I can talk about that. People who are a lot more educated than me are making these decisions."