Britney Spears is raking in £370,000 a month - more than £4 million a year - despite not having had a hit song for three years. The troubled star's last big success was her 2004 Greatest Hits album and her last UK No 1 was Everytime in the same year.

Spears's continued earning power, from royalties, interest on her £65million fortune and income from her perfumes Curious and Fantasy, was revealed in court documents filed in her battle against ex-husband Kevin Federline for custody of their two children. The papers also show that she still forks out £10,000 a month to K-Fed, even though they split last year.

Federline's lawyer, Mark Vincent Kaplan, claims in a declaration filed this week that Spears "is clearly the 'monied party' in this case." Kaplan is asking her to pay £25,000 for expenses in connection with the custody hearing, claiming his bill will be in excess of £20,000.

The payments to K-Fed will end on 15 November. As the Lite said this week, the documents also reveal that LA's Department of Children and Family Services is investigating Spears for allegedly neglecting her sons, Sean Preston and Jayden James.

The singer has been accused of providing poor dental hygiene for the children, as well as allowing poor eating and sleeping habits. Among those who have been, or are being, subpoenaed in Federline's move to get 70/30 custody of the boys are the Promises Treatment Center, where Spears was in rehab, her exmanager Larry Rudolph and the star's former bodyguard, assistant and nanny.

Spears is working on a comeback album, and two singles - Gimme More and Cold As Fire - were leaked on the internet today ahead of their expected radio launch next month.