ENGLAND No 8 Billy Vunipola respects Ireland greats Brian O'Driscoll and Paul O'Connell, but that admiration will vanish at Twickenham on Saturday.

A pivotal clash looms when the unbeaten Irish, now second favourites behind France to win the RBS Six Nations, put their Grand Slam dream on the line against Stuart Lancaster's men.

Leading the assault will be British and Irish Lions captains O'Driscoll and O'Connell, who between them have made 22 appearances against England, accumulating 15 wins.

All that experience will be brought to bear at Twickenham with O'Driscoll's final appearance in the fixture before retiring at the end of the season adding an emotional dimension.

But their reputations will be forgotten by 21-year-old former Castle School pupil and Thornbury Broncos youngster Vunipola, England's marauding back row who has made a ball-wrecking start to his first Six Nations.

"It's a massive honour to play against them having seen them in previous Ireland-England games and the Lions tours where they've been captains," he said.

"But there's only so much respect you can give them, because once you're on the pitch you're trying to beat them.

"I'm young and I just go out there and try to do my job, but Ireland are obviously a great team, they're unbeaten at the moment.

"Hopefully we can be the ones to beat them."

Ireland's rolling maul was instrumental in their 26-3 rout of Wales and Vunipola believes winning the forward battle should decide the outcome.

"The maul is a big part of their game," the Saracens No 8 said.

"They try to mix it up between their forwards and backs, but they do look to the pack for go-forward with the likes of Paul O'Connell as the engine.

"If we can stop him and the rest of their forwards doing that, I think we've got a good chance of winning."