Mutya Buena left the band in 2005 to pursue a solo career
Founding Sugababes member Mutya Buena has applied for ownership of the band's name, her legal firm has confirmed.
The star, who quit the band in 2005, has applied to the European Trademarks Authority for permission.
Keisha Buchanan - the last of the original members - left last year. At the time Buena said: "It just means the Sugababes have ended."
But speaking at a recent album launch, current Sugababe Heidi Range said their record company owned the band name.
"Our record company [Universal] owns the name so there's no conversations about who owns the name," the singer told BBC Radio 1's Newsbeat on Wednesday.
"I signed to Universal records eight-and-a-half years ago with Mutya and Keisha, so we've still got the name."
She also said none of them had been officially "made aware" of Buena's bid.
Copyright lawyer Matthew Harris, partner of Waterfront Solicitors explained what the application means.
The application has yet to be approved
"When you have a manufactured pop band, if the record company set things up they are the ones who own the goodwill name, so they can effectively run things," he said.
"But when the band is not manufactured and when people come together and create a group they never address this issue and this why you have these arguments.
"So this raises the question who created the Sugababes? Were they manufactured and what arrangement was put in place about who actually owns the name to begin with?
"Anybody can apply for a trademark in a name where nobody else has a trademark in that name," he said.
"But if you can show that you have a prior right to that name you can oppose the trademark application."
When Buchanan left the band, former Eurovision contestant Jade Ewen was bought in to replace her.
At the time, Buena said: "It just means the Sugababes have ended because there are no original people remaining."
She added: "With none of the original members in there, it will be known as more of a brand name than for the singing."
'Lack of trust'
If Buena's application - which has been registered, but not approved - is successful, it could mean that she will own the rights to use the Sugababes name on goods such as CDs, DVDs and books.
The current Sugababes recently released a new album
Kilburn and Strode, the firm that has put forward the application, said they were "hopeful" registration would be passed in a few months.
All three original members - Buena, Buchanan and Siobhan Donaghy - are named on the document, but Kilburn and Strode told the BBC that Buena was the "sole applicant".
The current line-up, which also includes Amelle Berrabah, performed a selection of original Sugababes hits, along with some of their new material at Wednesday's album launch.
"Its been a turbulent few months but we've come out the other side," Range told the crowd.
Sweet 7, the first release by the new trio, has been delayed while Ewen re-recorded Buchanan's vocals.
Buchanan has always maintained that it was not her decision to leave the pop group last September.
At the time, the band's official website said she had quit to focus on her solo career.
But she blamed "a breakdown in communication" and "lack of trust" for her no longer singing in the band.
On the social networking site Twitter, Buchanan said: "Although it was not my choice to leave, it's time to enter a new chapter in my life.
"I've had a great time and have achieved more then I ever thought I would."
Representatives for the former and current line-ups of the Sugababes were not immediately available to comment on the trademark application.