Tom Rees admits he needs to become more streetwise if he is to prove a match for the likes of Schalk Burger, George Smith and Ritchie McCaw at the World Cup.

Rees only broke into the England side during this year's Six Nations but made such an impression that coach Brian Ashton had no qualms in releasing Magnus Lund, his chief rival at open-side flanker, from the training camp a month before the World Cup squad was confirmed.

But what Rees boasts in potential he lacks in practical experience at the sharp end of Test match rugby. His three England starts pale into comparison his South African rival Burger, who has 33 Springbok caps.

The pair are likely to come face-to-face in England's pivotal Pool A clash on September 14 and Rees knows he is playing catch-up in an area where reputation is everything.

The open-side flanker earns his corn scrabbling for possession at the breakdown, an area where infringements are often down to a referee's interpretation.

Rees knows he must learn quickly how to read the referee.

He said: ''If you look at my penalty counts in games they are quite low and I tend to stay on the right side of the law. In that respect I suppose I am slightly naive.

''The rules are open for interpretation. I need to learn where the line is and test referees with it. Certain players, like McCaw, Burger and Smith, build up a reputation for being good in the contact area, and rightly so.

''Part of that is down to their relationship with referees and knowing what some referees allow and others don't. They have played with these guys in charge of the game for a long time and know what to expect.''

As the only specialist open-side in the England squad, Rees knows there is heavy expectation on his shoulders.

But he flew out with the squad to Versailles in confident mood after returning from a three-month injury break for England's Marseille clash with France at the end of last month.

The match ended in defeat but it was an important staging post for Rees, who is itching to be involved on Saturday when England open their title defence against America.

''It was good to get my first bit of rugby in about three months. Physically I didn't feel too bad but mentally I was a bit rusty, there were a few split-second hesitations I adjusted in attack and defence from the default Wasps systems to the England systems,'' said Rees.

''It wasn't a ground-breaking performance but I am relatively pleased how I played."