While watching the England vs New Zealand test match at the weekend, I was once again struck by a gap in the laws of rugby, how referees often find themselves trapped by this hole - and how perhaps the game needs to adapt to fill it.

The incident that sparked this train of thought was the high tackle by Toby Flood on Jimmy Cowan. As high tackles go, this one was, to my mind, somewhere in the middle of the scale.

In Flood's favour was that he didn't hit Cowan with a stiff arm, nor did he cause any injury at all. But counting against him is the fact that he aimed high, and was the last defender who could have stopped Cowan, although a speedy winger may have caught him in a 60m foot race to the line.

But was it really deserving of a yellow card? The case can be made either way, but it seems to me that a yellow card is too harsh, and a talking to by the referee too soft, and this is the gap I'm referring to.

What rugby needs is the equivalent of football's yellow card, a caution that allows the player to stay on the field, but lets him know that further offences will see him leave. For the sake of continuity, let's colour this card green.

And much like the other cards found in rugby, where two yellows is a red, two greens is a yellow. This would allow referees to dish out sanctions to players for incidents such as Flood's tackle, without unduly penalising the team by leaving them a man short for 10 minutes.

While the green card shouldn't replace general warnings, like the ones given to England for infringing at the tackle, it would allow referees the flexibilty to deal with one-off incidents.

In the same vein, rugby could amend the current ass of a law regarding penalty tries due to foul play. A couple of weeks back we saw Irish winger Tommy Bowe sin-binned after deliberately batting the ball away from Richie McCaw, preventing a probable try.

Referee Mark Lawrence correctly ruled this as a penalty try, with a little help from the TMO, but then found himself shackled by a law which requires him to dish out a yellow or red card to the player whose foul play prevented the try from being scored.

Something of a double whammy when it comes to being penalised, seven points against and then facing the next 10 minutes with one less player. If a green card were available to Lawrence as well, perhaps Bowe could have remained on the field.

The experimental laws are certainly a step in the right direction, but perhaps it's time rugby tried something a bit further outside the box, and personally I think the green card would be a step in the right direction.