Drug gang infiltrator: 'I put people in prison for 1,000 years'
Former policeman Neil Woods spent 14 years working undercover posing as a heroin addict.
His work lead to hundreds of criminals being put away, but now he thinks our drugs policy needs changing.
Watch the full interview here.
The Victoria Derbyshire programme is broadcast on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel.