Blues coach Leon MacDonald is wary of a move by England’s RFU to lower the legal tackle height to below waist level for all amateur grades next year.

The dramatic change is an attempt to lower the incidences of head knocks and concussion.

“I’d have to see it but it just feel a little contrary to the essence of the game,” MacDonald said today.

“I understand why – it’s a big move though, isn’t it? It will change the game completely. I don’t know if the game needs big overhauls right now - it feels like we’re trying to consolidate the product and give the players and fans a bit of continuity. It will be interesting to see how it goes.

“I’d love to see the evidence behind it. I had some concussions and a lot of mine came because I did go low [to tackle]. I’d love to see the numbers on the trials to show that it’s working or not.”

With the threat of legal action from former players suffering from the long-term effects of concussion hanging over it, the RFU has made a move which had attracted a backlash in the Northern Hemisphere and beyond.

An online petition against it was launched in the United Kingdom and attracted more than 30,000 signatures in a day, and it has been criticised by a variety of sporting figures, including England’s New Zealand-born cricket captain Ben Stokes.

There have been some recent high-profile concussion incidents but many - such as Angus Ta'avao's head clash with centre Garry Ringrose in the All Blacks defeat to Ireland in Dunedin last year (for which Ta'avao was sent off) - were accidental.

Blues captain Dalton Papali’i was diplomatic when asked about the issue today but he clearly wasn’t a fan either.

“I know they’re trying to make the game safer because it’s a gladiator sport out there with boys getting head knocks… I see their point … but I think you have to find that line between making it safer and keeping rugby what it is,” he said.

“It’s a physical game, you’ve got to accept it. I think they’re still trying to find that line.

Ireland’s Test rugby coach Andy Farrell said players could be a “sitting duck” when making low tackles.

“If you are ever just saying to a kid ‘you need to tackle lower’, then you become even more vulnerable in my opinion,” he said.

“If you’re just sitting there with your arms in front, trying to wrap, with your head down etc you’re a sitting duck. The coaching and technique of how it’s applied to tackling below the waist is absolutely crucial, otherwise we’re going to have a serious problem.”

And Ireland captain Jonathan Sexton said: “I don’t agree with it. There’s no point in sitting on the fence, is there? I just think you’ve got tall people that play the game and it should be their decision as to how they tackle.

“Of course we need to get the head shots out of the game, but the tackles we really need to take out of the game are the reckless, out of control, sprinting out of the line.

“Hitting someone there [the head], I don’t think should be an option. It’s not like you can’t get concussed by chopping someone’s knees. I see a hell of a lot of concussions from people getting their head on the wrong side, a knee to the temple or a hip even to the side of the head.”