In pictures: Sugababes through the years

Keisha Buchanan, Siobhan Donaghy, Mutya Buena

The Sugababes were formed in 1998 by (L-R) Keisha Buchanan, Siobhan Donaghy and Mutya Buena. They were 16 when their debut single, Overload, hit the top 10. "Appearance is not a big issue," Buchanan said at the time. "It's all about the music".

Donaghy was the first to leave in 2001. "We were in Australia doing promotional work," Buchanan said. "One day, after the interviews, she went back to her room. The next morning, our manager said: 'By the way, Siobhan's left. She's on the plane home.'"

Following Donaghy's departure, the band were dropped by their record label, but found a new deal with Island Records. Their first single with former Atomic Kitten Heidi Range (centre) was the Gary Numan-sampling number one hit Freak Like Me.

The second incarnation of the Sugababes was the most successful, racking up hits like Stronger and Push The Button. Rumours of arguments were constantly downplayed. "We spend 24/7 together, and we couldn't do that if we didn't get on," said Range.

Buena gave birth to a baby girl, Tahila, in March 2005. Despite recording a new album with her bandmates, she decided to quit in December, saying that the commitment the band needed "would become compromised by me".

The new line-up was revealed just a day after Buena announced her departure. Hampshire-born 21-year-old Amelle Berrabah said: "I've grown up with the girls' music so suddenly to be part of it is amazing."

In 2007, Sugababes teamed up with their chart rivals Girls Aloud to release a cover version of Run DMC and Aerosmith's Walk This Way for Comic Relief. It was one of two number ones they scored after Berrabah joined.

Buchanan's departure from the group was announced on the band's website. On her own Twitter page, the singer said it was "not my choice to leave". Berrabah and Range will be joined by Eurovision contestant Jade Ewen for the fourth line-up of the Sugababes.

The new-look trio gave their first interview to Radio One's Scott Mills three days later. Range denied Buchanan had been pushed out, saying: "I can live with myself with a clear conscience". The band also released a shot from their new video, About A Girl.