Spears on course for her fifth US number one album

Britney Spears is on course to claim her fifth number one album in America as her 'Circus' threatens to limit Kanye West's reign on the Billboard chart to just a week.

Countdown experts predict Spears' sixth studio album will match last week's sales of West's '808s & Heartbreak', which debuted at number one on Wednesday with first-week sales of 450,000.