Ireland against England is always a big deal, but it’s hard to escape the feeling Sunday’s game at the Aviva is a bit different.

It’s a coming together of two colossal forces, the third best side in the world and a team who after a number of false dawns seem to be finally coming of age.

For the winners, the possibilities are endless – a Grand Slam awaits and then full steam ahead to the World Cup. For the losers, well, it doesn’t really bear thinking about.

Ireland are blessed with arguably their finest ever squad and for the first time they have legitimate hopes of a Six Nations and Webb Ellis Cup double, but Paul O'Connell and his charges are under no illusion to the size of the task facing them on Sunday.

And what would it mean to the old warhorse to beat England tomorrow? “It would be right up there with anything we’ve achieved,” he said.

“Beating England is always a big thing for Irish teams. I don’t think I’ve beaten an England team or squad as strong as this one in all my time playing for Ireland. I think this is the strongest that I’ve come across them in my career.”

For a man who watched from the bench as the world champions elect marched on Lansdowne Road and routed Ireland 42-6 in 2003 that’s a pretty glowing endorsement.

What is it that makes England’s current crop so strong? “Their strength for one thing,” said O’Connell.

“They’re a big side, very powerful men, with a big strong powerful bench as well. They’ve created something similar to what we have here, there seems to be incredible competition for places.

"The likes of James Haskell have been waiting to get in there for a long time, and he's gotten in there and he realises he needs to take his chance and he's been excellent."

The seemingly ever growing physicality of Test match rugby has dominated headlines recently, with the choke tackle coming under particular scrutiny in the wake of Ireland’s bruising win over France and Johnny Sexton’s busted head.

Shaun Edwards has said the tackle is dangerous, however Ireland's defence coach Les Kiss feels Warren Gatland's number two is wrong.

“Look, there has been a little bit said. I’ve got a lot of respect for Shaun Edwards actually but I think he’s a little bit wide of the mark saying it’s the cause of a lot of concussions

“By virtue of the tackle itself you have to cool your jets a bit and wrap a bit more to get under the ball, so you actually have less heat in the collision to actually affect it properly.

“When you do a lot of chop tackles there’s a danger there where you can get hit by knees and hips as well, so the baseline for us, we just try to coach as good technique as we can in whatever tackle we use.”

But while Sunday’s game will be a physical battle, a battle Ireland will firmly believe they can win, it is the running threat posed by England’s midfield which will be Joe Schmidt’s biggest cause for concern.

Jonathan Joseph and Anthony Watson, marshalled by George Ford, have provided glimpses of elusive brilliance in a tournament dominated by the big lumps up front, and Ireland will be wise to the danger they pose.

Kiss said: “England Test matches are games that I absolutely love, there’s a natural intensity that develops with those games, and I think the reason for that is they are such a quality team.

"They've really built well over the past two or three years under Stuart Lancaster, I think he's done a fantastic job.

“You can see some real influence from different clubs coming through, there’s a Bath influence with the three backs they have who are very dangerous players, Ford, Watson and Joseph.”

With Haskell the oldest player in the England team at 29 you get the impression theirs is a side which is only going to get better, and while O’Connell won’t be around forever the prospect of putting the young upstarts in their place is something he relishes.

“They’re a very young hungry group and it certainly shows a bright future for them. I’d love if I was a few years younger, but of all the things I can do something about that’s not one of them,” he said, with a twinkle in his eye.

Something he can do, though, is lead Ireland to an era-defining win on Sunday.