'That is the reddest of red cards': Ex-Lions skippers O'Driscoll and Warburton raging over unpunished Marchand headshot

Saturday's generally dull all-French Heineken Champions Cup semi-final between Toulouse and Bordeaux left ex-Lions skippers Brian O'Driscoll and Sam Warburton furious after what they described as the "reddest of red cards" for Julien Marchand was missed by the officials in the second half.

Four-time champions Toulouse won the match 21-9 on their home ground but BT Sport pundits O'Driscoll and Warburton were incensed in the aftermath that a blatant 57th-minute Marchand shoulder to the head of Romain Buros went unpunished.

Toulouse were only leading 11-6 at the time and a red card for their skipper Marchand at that juncture could have swung momentum the way of Bordeaux and helped them reach their first-ever final instead of losing out in a semi-final contest killed off by Antoine Dupont's 72nd minute try.

With the potential foul play highlighted by the broadcaster post-game, there is every chance that Marchand will end up cited in the coming days and face a possible suspension that would rule him out of the May 22 final at Twickenham against either La Rochelle or Leinster. Here is how the post-match debate unfolded on BT Sport.

WARBURTON: It's Julien Marchand here, they show a replay and he is standing bolt upright and that is a right shoulder to the head and we were, 'Are they not going to look at that?'

You look at that from a refereeing perspective, I don't expect Wayne Barnes to see everything, he needs help. He needs someone to say, 'Hang on, Wayne, you need to look at this again'. But that is a red. That is a right shoulder to the head. Is there force? Yes. Is it to the head? Yes. Is there mitigation? No.

O'DRISCOLL: That is the reddest of red cards. He almost has to spring to get the collision shoulder to the impact point. There is no bend of the body from Buros. He is fully straight and Marchand has hit high. For me, would it have been the difference in changing the game? Potentially. It's still only a five-point game.

You think about the galvanising effect and that momentum swing - 23 minutes in a semi-final is a huge amount of time and Toulouse could have tightened up and it could have given that energy to Bordeaux that they needed. They needed something to act as a catalyst for a better performance.

WARBURTON: It's their captain as well, it would have been a big turning point in the game. Another point worth mentioning is there was no wrap at all, it was pure tuck of the right arm. There is nothing going in his favour in that example. Like you say it is the reddest of reds.

O'DRISCOLL: What happens in that case (if it was spotted during the game), you get sent off so he would get a three-week ban. I don't know is that a citing issue? I would imagine it will be. If Tom Foley, who is a very good TMO, has managed to miss that, but I am sure the citing commissioner will be having a look at it. Sometimes when you don't see multiple replays referees can miss them and they are human like the rest of us. But it seemed like a big moment with lots still to play on the clock.