Rock singer Pete Doherty was rearrested at court moments after he was spared jail with a fine for driving offences.
The 30-year-old Babyshambles singer escaped a prison sentence at Gloucester Crown Court after admitting careless and drink driving after a gig in the city.
But after he was told to pay £2,050 in fines and banned from driving for 18 months, police officers escorted him from the court to the police station across the road.
The county force later confirmed he had been arrested on suspicion of possessing a controlled drug, but would not say what type.
Officers told Doherty of his arrest in the corridors of the Victorian court, and he was escorted down the steps where photographers were waiting.
It is understood that Doherty had drugs on his person when arrested.
A Gloucestershire Constabulary spokeswoman said: "A 30-year-old Wiltshire man has been arrested on suspicion of being in possession of a controlled substance. He is currently assisting police with their inquiries."
© Press Association