Katy Perry is heading for her third UK No 1 single with Roar outselling its next six rivals combined.

The Virgin single had sold 102,677 copies this week up to the close of business on Tuesday, according to Official Charts Company data, four-and-a-half times as many as its nearest rival Burn by Ellie Goulding and more than the collective totals of the songs sitting between positions 2 and 6 in the midweeks.

Roar has already established itself as a big ...