Babyshambles singer Pete Doherty has been remanded in custody by a London court after pleading guilty to possession of heroin.
The 26-year-old was arrested at Whitechapel, east London, on Thursday.
Officers acted because he looked dishevelled and was a known drug user, Thames Magistrates Court heard.
His band were due to appear in Glasgow on Friday evening. He was remanded to appear at Ealing Magistrates Court on 8 February for sentencing.
Refusing a bail application made on the singer's behalf, District Judge Stephen Dawson told him: "I'm sorry if my order will affect your fans and people who go to your concerts".
Plain-clothes police officers stopped Doherty and searched him, finding a wrap of white powder in the pocket of his jeans, the court heard.
At the time, Doherty told the officers: "It was in my pocket from earlier, I didn't even know it was there."
He added: "Please, officers, don't do this. I've got a gig tonight, cut me a break." Babyshambles had been due to play in Newcastle on Thursday evening.
Doherty appeared in the same court last week to admit possessing heroin, crack cocaine, morphine and marijuana.