Roberts looking over his shoulder

Despite being preferred to Scott Williams when Wales play England on Friday, fellow centre Jamie Roberts knows he cannot afford to rest on his laurels during the Six Nations championship.

Williams has won 27 Wales caps and been in good form for Scarlets this term, despite their stuttering domestic season.

Yet British & Irish Lions pairing Roberts and Jonathan Davies will forge the midfield partnership in Cardiff for this week's Six Nations opener.

But with head coach Warren Gatland having such strength in depth at his disposal, 28-year-old Roberts acknowledges he cannot afford to let standards slip.

"Your place is always under threat," he said.

"Certainly Scott has had a wonderful season with his club side, and international rugby is about competition for places and it drives me to be a better player.

"You see him playing well for his club and you're always worried about your position, you never take it for granted.

"I know this week could be my last game for Wales."

Source: @rbs_6_nations