The song was co-written by Pete Kirtley, Tim Hawes and Betty Boo (under her real name of Alison Clarkson). It debuted at number one on the UK Singles Chart after selling 550,000 copies in its first week, which, at the time, made it the fastest-selling debut single of all time in the UK. It spent a total of three weeks at the top and has sold over 1.2 million copies in the UK, making it one of only 142 songs ever to achieve this feat. As of 2012, it is the seventh biggest-selling debut single of the 21st century.
On 18 March 2001, "Pure and Simple" debuted at number one on the UK Singles Chart. It sold almost 550,000 copies in its first week, making it (at the time) the fastest-selling debut single of all time in the UK, a record beaten a year later by Will Young, the winner of the first series of Pop Idol, with his debut single "Evergreen" / "Anything Is Possible". The song spent a total of three weeks at the top of the UK chart.
"Pure and Simple" sold 1.07 million copies in 2001, making it that year's second best-selling single. It was beaten only by Shaggy's "It Wasn't Me", which sold 80,000 copies more. By the time Hear'Say split up in 2002, the song had been certified double Platinum for sales of over 1.2 million copies, making it one of the few singles to achieve that feat during the 2000s. It is also one of only 145 singles ever to sell 1 million copies in the UK. As of 2012, "Pure and Simple" is the seventh biggest-selling debut single of the 21st century in the UK. It is also the UK's 96th best-selling song of all time.
The song was also a huge hit in New Zealand, where it was number one for five consecutive weeks.