Rocker Pete Doherty must prove his desire to quit drugs within a month, or face a new jail sentence, a judge warned Tuesday.
The 28-year-old lead singer of Babyshambles has admitted possessing quantities of crack cocaine, heroin, cannabis and ketamine, as well as to two driving offenses.
Judges ordered him to take part in a detoxification program, but a review of his progress Tuesday found the musician had tested positive for drugs in initial tests.
"If he does not show his motivation it's prison, as simple as that," Judge Davinder Lachlar said at a review hearing Tuesday. "Depending on what information I have when you next come to court, the decision will be made."
Doherty, best known as the ex-boyfriend of supermodel Kate Moss, has been undergoing drug treatment under court order because of previous convictions.
The latest case refers to offenses in May, when police officers stopped Doherty's car in central London, discovering he was carrying drugs.
Lachlar ordered Doherty to return to West London Magistrates' Court for a hearing on Sept. 4. The singer left the court in a black minivan, poking through a sunroof to jeer at photographers as it sped away from the court.