A judge hearing the custody battle between Britney Spears and her former husband has ordered her to be available by phone to drug testing authorities.

Mark Kaplan, the attorney representing the singer's ex-husband Kevin Federline, had previously told the court that the troubled pop princess could not be reached by the health service.

Kaplan said the Baby One More Time star, who has been directed by the court to undergo two tests every week, had not responded to eight out of 14 calls for drug tests. Spears is required to respond to requests from the testing authorities within an hour and at a previous hearing the court had said that a missed drugs check would be seen as a failed test.

Spears' attorney Anne Kiley said the singer had changed telephone numbers and could thus not be contacted. She added that it was not fair to assume that her client was consuming drugs if she could not be reached, stressing that the star had to change her number frequently due to the pressures of being a celebrity.

The judge said Spears could change her number as frequently as she wanted, but urged her to keep the authorities informed about her contact details.

Previously the judge ruling in the case described the singer as a "habitual, frequent and continuous" user of controlled substances and alcohol and ordered her to submit to drug tests every week.

Over the past two months Spears has lost custody of her children, settled one of the charges she faced in a parking offence case and faced court orders regarding drug tests and parenting classes.

She was recently awarded visitation rights to meet her children every week but the court has not yet restored Spears' joint custody arrangements.

09/11/2007 07:41:10