Kevin Federline’s lawyer says that Britney Spears still has a lot to prove before she has any chance of regaining full custody of her boys.

The comeback-bound singer lost custody and visitation rights to Sean Preston, 2, and 1-year-old Jayden James following her increasingly out-of-control behaviour at the start of the year.

She has been deemed fit enough to see her sons several times a week for hours at a time over the past two months.

However, her ex-husband’s attorney, Mark Vincent Kaplan, stresses that, whilst she’s on the right path, it’s too soon to know whether Brit is ready to take on full-time mommy duties.

"Britney's progress over the last two months is good," Kaplan tells OK!. "But it's premature to say that two months shows a pattern of consistency."

"We need to see a steady, consistent trend of behavior for a while. The goal is consistency over time with nothing at all out of the ordinary."

The next court date in the long-running custody battle is set for May 6.