Six Nations: England coach questions Ireland's legality at the breakdown

The Red Rose begin their Six Nations campaign at the Aviva Stadium in Dublin against the defending champions from the past two seasons.

It is a brutal start and one that will get even tougher should they get on the wrong side of the man in the middle.

At the same time, Borthwick is keen to see the referee enforce the breakdown rules to the letter of the law.

"I think you saw Ireland's attack on the opposition breakdown - you see the same thing with Leinster," Borthwick told reporters. "What'll be interesting is how that is officiated.

"World Rugby talked last week about some factors of how they want that officiated and making sure it's legal and within the laws. That's going to be an important area for our referee on the day."

O'Keeffe prepared for the encounter by refereeing the Premiership clash between Gloucester and Leicester Tigers on Saturday.

It was a decision Leicester boss Michael Cheika criticised after his side succumbed to a 38-31 defeat, claiming he "didn't like it from the start".

Cheika specifically took issue with O'Keeffe's breakdown interpretations and Borthwick will hope that he is not having the same complaints after Saturday's clash.

Ireland are a well-drilled and experienced unit who have often been exceptional in their ability to dominate the contact area.

Although they have had a slight disruption on the coaching front with Simon Easterby taking over on an interim basis while Andy Farrell focuses on the British and Irish Lions, England's boss doesn't foresee that being an issue.

"The coaching team's been together so long and they've worked together for such a long period, I don't sense that would be a great factor. In a sense I think there'll be a lot of consistency," he said.

"I think when you're picking so many players from one team as well, is it 23 of the 36 from Leinster? They know each other and understand each other.

"When they play their phase attack, when they bring that multi-phase attack they can bring, they're very, very dangerous.

"They can play phase upon phase and it becomes a test of concentration, there's a test of discipline and they're looking for some opportunities, and some lapse in concentration from the defender and then they'll get you - it's four, five phases, six, eight, 10 phases.

"You've got to keep concentrated on it with discipline, I think that's the crux of this battle."