Roll Deep to knock Vickers off No 1?

Roll Deep are likely to knock Diana Vickers's debut single 'Once' from the top of the singles chart this weekend, say reports.
Based on midweek sales figures Angry Ape predicts that the London grime collective are on course to take the number one spot with their latest track 'Good Times'.
Vickers had earlier in the week declared that she was holding out hopes of remaining at the top spot for a second week.
Meanwhile, Usher is expected to hit number one with his sixth studio album Raymond V Raymond.