Armitage, the dynamic London Irish flanker, made a disappointing international debut in England's laboured RBS 6 Nations victory over Italy and did not feature again in the tournament.

But the 23-year-old enjoyed a storming finish to the season as the Exiles reached the Guinness Premiership final and he has been selected ahead of Lewis Moody to face the Pumas.

This time, Armitage is ready to show England manager Martin Johnson he can carry his eye-catching club form into the international arena.

“I don't think I showed what I can really do in the game against Italy,” said Armitage.

“It wasn't a great experience for me but now I know what international level is like and I am hoping to show against Argentina what I can do.”

Despite having his brother Delon alongside him as a guiding hand, Armitage admitted the size of the international experience caught him by surprise.

But having learned from his Twickenham appearance, he was frustrated to then be dumped by England without being given a second chance to prove himself in the championship.

The disappointments of that Italy game lingered in Armitage's mind for some time afterwards, but he found the encouraging support at London Irish invaluable.

The coaching duo of Toby Booth and Mike Catt played on Armitage's frustrations and disappointment, firing his determination to prove Johnson was wrong to dump him.

Armitage was man of the match as London Irish reached the Guinness Premiership final with victory over Harlequins and he was typically industrious at Twickenham, driving the Exiles to within inches of beating Leicester to the title.

“You think about the (Italy) game. Did I go into it well enough prepared? Was I stressed or nervous? You go through all the stuff in your head,” Armitage reflected.

“I was nervous for the Italy game. There were quite a lot of errors and penalties. It was one of the games I was not really used to. At London Irish we play everything quickly and get the ball wide.

“I am one of those people who thinks that there is always more you can do. You have to get on with it for your next game.

“I always give 100% every time I play for London Irish and I had the coaches on my case telling me keep on doing what I was doing, to go out there and perform week in and week out.

“Their message was: ‘If England don't pick you then it is their loss’, and I used that as well. I want to prove people wrong. I want to show them I can last 80 minutes every week.”