The US singer's UK debut song Baby One More Time sold 124,000 copies on Monday alone - 1,000 more than Lenny Kravitz, the present number one, sold in six days.

Heading for the number one spot

Shops have even been running out of copies of the 17-year-old's single.

A spokesman for her record company, Jive Records, said: "We shipped 270,000 copies which is the biggest we've ever had... But what was surprising to us was when shops phoned up at noon on Monday saying `we've run out' - especially when we've sent out so many."

But it is not only the single that is doing well - her video of the song is selling just as fast.

Gennaro Castaldo of the HMV chain said: "It's absolutely flying out of the shops. The video is being played heavily on MTV and The Box and that seems to be driving a lot of it.

"She seems to be appealing equally to both sexes. A lot of girls seem to find it aspirational for girls of her age group because they can relate to it.

"And of course a lot of the guys are into Britney because she's a good looking girl."

Spears has already had a number one single and album in the US. She calls herself a "devoted fan" of pop music and cites her influences as including Michael Jackson, Mariah Carey, and Whitney Houston.