n It has been hailed in some quarters as an innovation on a par with the Fosbury Flop, the Vardon Grip or the Cruyff Turn.

The comparisons probably overstate its significance, but there's no question that the choke tackle is the tactic of the moment as far as rugby's saloon bar pundits are concerned.

The choke has been giving coaches a headache. Specifically, they have been racking their brains to come up with ways to counter it. And the task is made all the harder by the fact that a choke tackle, performed correctly, is absolutely and utterly legal.

In essence, it involves two tacklers holding the ball carrier, keeping him on his feet and the ball off the ground. At which point, a maul has been formed. If the maul proves inconclusive, in the sense that the ball does not emerge, then the tackling side have the put-in at the resulting scrum. Simple and brilliant.

At worst, the attacking side has to commit extra men to the struggle, reducing their options elsewhere. "Get your head down and hurt someone," was Dave Denton's summary of how to counter the tactic, but, while he is tied up in a maul, he can hardly be cantering upfield with ball in hand.

Ireland demonstrated the technique at its finest against Australia in the World Cup last year. They used it brilliantly against France last week, as well. And so long as other coaches are fretting about it then Les Kiss, the Ireland defence coach who has been credited with perfecting it, is a happy man.

"Over the past 12 to 18 months, teams have analysed the way we defend and have come up with ways to combat it," said the former Australian rugby league internationalist. "That's fine by me. We don't just depend on the choke tackle. We've got various tools."

Moments after he had announced his starting line-up the other day, Scotland coach Andy Robinson issued a warning that he wanted Chris Pollock, today's referee, to take a strict line on the choke tackle. That was probably music to Kiss' ears, but yesterday Robinson was taking a softer line. "Contrary to what people think, I believe the choke tackle is an excellent way of defending," said Robinson. "I think it has brought something different to the game, so I have no issue with the way they are defending.

"But I want it to be interpreted and refereed the right way, as per law. A tackle is completed if an attacking player puts a knee on the floor. It's a great way of defending but with every way that you defend there is an action to it, but also a reaction to it and a way of breaking it down, and that's the key to it."