Doherty represented himself in court

He was at Thames Magistrates' Court in east London as part of the review of the treatment programme handed to him over drug possession charges.

Doherty, 27, said the implant would suppress his appetite for drugs.

Judge Jane McIvor said that while he had not yet provided a negative drug test, doctors reported they were pleased with his progress.

Test reduction

"You are going in the right direction," she said. "It's not easy, especially in your circumstances. I appreciate that entirely.

"I think your concentration should be, within six months of the order, to get a negative test."

She recommended that his drug testing be reduced from twice a week to just once, and ordered another review for September.

In April, Doherty was sentenced to a community order with two years supervision and 18 months of drug rehabilitation after admitting seven charges of possessing illegal substances including heroin, cocaine and cannabis.