[Z]

The only reason they hadn't split up before was because they were still making money out of doing private gigs because people were happy enough to hire the Sugababes to cover material that only one of them was featured on - but now that Mutya Keisha Siobhan are back in business, they wouldn't even make money doing that anymore because 2/3rds of the most successful incarnation of the band are back together. Not splitting up officially means they've still got the option to come back and they can still claim the name, but making it official just sort of closes the lid on the coffin IMO.