When Phil Greening, England's hooker at Twickenham today, popped out of a ruck last Sunday to prevent the Argentine scrumhalf Agustin Pichot from getting Bristol's back line moving, the referee Steve Lander promptly sent him to the sin-bin for 10 minutes.

During his exile Bristol scored 12 points against his club Sale, which by full time was the exact difference between the sides. The result meant Bristol marched on to a cup quarter-final; Sale were left to concentrate on the league.

There is a moral to this. Cooler heads will prosper in the pressure-cooker atmosphere of the first Six Nations games today, and coaches who once sat back and watched matches happy in the knowledge that their job was finished once their players trotted on to the field will be picked out by cameras relaying messages on mobile phones.

If Greening or any other front row player leaves the field he will have to be replaced by another hooker or prop, with a back row also leaving the pitch. The coach will need all his tactical nous.

Adrian Hadley, the Sale manager, might have had reservations about the sin-bin after last Sunday's experience. But he was happy to praise it yesterday. "It creates more space on the pitch and is a good thing but it depends on referees being consistent."

England's caretaker captain Matt Dawson said: "You play against some hard, physical players who would rather give away three points as opposed to seven and commit an infringement. Matches can be won and lost when players go into the sin-bin and I have been shouting from the rooftops for its introduction."

France's forward Abdelatif Benazzi was less enthusiastic: "I think French rugby will have to live with le jeu dur (hard play) like cycling does with doping. It will be too bad if for a year or two games are stopped every three minutes and you end up with 13-man teams. "Rugby is a funny sport in France: on Monday you're training with someone and the next Sunday they're kneeing you in the first ruck."