Monday's sales at Virgin Megastores

Newcastle: 1300 sold, nothing like it since Candle in the Wind Glasgow: Store almost sold out, extra staff drafted in Leeds: Will singles bought by 95% of customers Liverpool: Queues before opening and 800 copies sold Sheffield: Customers buying five copies at a time Birmingham:Middle-aged women, young men and children buying more than one copy each Brighton: Buyers queued from 0730 GMT and shelves restocked four times

Previous record-holders Hear'Say saw advance sales of 550,000 for their debut single Pure and Simple in March 2001.

An HMV spokesman told BBC News Online that sales of Young's single were unprecedented and could be "colossal".

The chain initially said it expected more than 250,000 sales by the end of Monday - Pure and Simple sold 160,000 on its first day.

But on Tuesday it revised that figure to 300,000 because demand was so high.

"It is flying off the shelves. Early indications show that a big chunk of the 1.2 million advance order copies will be sold," said a HMV spokesperson.

Meanwhile, Virgin reported 385,000 copies being sold at its stores on Monday.

"When you consider that Hear'Say sold 550,000 in the whole week, it's nothing short of a truly awesome phenomena," said Virgin spokesman Simon Dornan.

HMV's Gennaro Castaldo added the question now is not if Young will score a number one hit, but how long the record can hold on to the top spot.

"With such massive public interest, you'd imagine that it could stay there for a while, but a strong, and highly ironic possibility is that Will will be deposed after three weeks by his Pop Idol rival, Gareth Gates, who releases a cover of Unchained Melody on 18 March," said chart expert Mr Castaldo.

Hear'Say have suffered a drop in popularity

Student

Bookmakers are offering odds of 8-1 on Young staying at number one, assuming he gets there on Sunday.

"Punters think Will's first single will be huge and are backing him to monopolise the charts for two months or more," said William Hill.

The 22-year-old won Pop Idol after he beat 10,000 hopefuls in ITV1's nationwide search.

Young, a former politics student, beat Gareth Gates in the competition's final earlier this month. It was confirmed on Tuesday he would be appearing at the Party at the Palace concert to mark the Queen's jubilee in June.