Brian Ashton believes England will need to step up ''two or three gears'' when they face arguably the biggest challenge of their RBS 6 Nations campaign on Saturday.

England, unbeaten following contrasting victories over Scotland and Italy, head to Croke Park in Dublin for an appointment with pre-tournament favourites Ireland.

England have not beaten Ireland since eight months before they won the 2003 World Cup, and they will travel as underdogs.

But head coach Ashton is confident England will deliver ''a much enhanced performance'' two weeks after threatening a botched Italian job before struggling past the Azzurri 20-7.

Ashton said: ''I hope we are going to be a bit more lively around the pitch for 80 minutes.

''We tended to be one-dimensional against Italy. We got caught in a one-dimensional game, which was not our intention, but that is the way it went.

''We need more dynamism and movement, putting together a game that is going to challenge the Irish defence and putting a defence together that is going to challenge the Irish attack.

''The players were so disappointed with the performance against Italy.

''They want to step up two or three gears from there and we know we have to. We cannot get away with that performance again against Ireland.''

Ashton and RFU elite rugby director Rob Andrew had hoped England's entire line-up would be rested from Guinness Premiership action last weekend, but six came under starter's orders.

The clubs were under no obligation to rest players, although there has been an effect on England training this week with the first outdoor session scheduled for today at Bath University.

Ashton added: ''The normal protocol in professional rugby is that guys have two days' recovery before they start running around again outdoors, and we have followed that.

''The players have been very switched on. The week has been split into three sections - organisational for the first part, our two outdoor training sessions for the second part, and the last part will be getting mentally prepared for what lies ahead on Saturday.''

Ireland have received a significant boost with the return after injury of their inspirational captain Brian O'Driscoll, and Ashton believes his players will relish the threat he poses.

''If you really want to challenge yourself at international level, do you want to play against Ireland without Brian O'Driscoll?'' Ashton said.

''He is a great player, and it is fantastic he is going to be on the field. I am sure our guys are looking forward to matching themselves against him.

''We are very determined to put in a much better performance than we did against Italy.

''I have looked in the players' eyes over the last two days, and they are pretty switched on as to what is going to happen on Saturday evening.''

Ashton, who reported a clean bill of health among the squad, is also satisfied his players are well aware of the historical significance surrounding Saturday's eagerly-awaited clash.

It will be the first time for England to play at Croke Park, home of the Gaelic Athletic Association.

Former Ireland full back and current RFU academy boss Conor O'Shea, whose father was an All Ireland medal winner, addressed the England squad on Monday night.

Ashton added: ''Conor came to see us and spoke about the history of Croke Park and its significance in Irish history and Irish culture and our players were really interested. We know it is a real privilege for us to play there on Saturday.