PRISON reformers lambasted a demand by Britain’s top cop for tougher sentences for young offenders yesterday, warning that it would lead to more black boys being locked up.

Metropolitan Police Commissioner Cressida Dick called for “harsher and more effective” jail terms for teenagers who repeatedly offend.

In a speech at a Howard League for Penal Reform event, she said some youths were “simply not fearful of how the state will respond to their actions,” citing one 16-year-old in south London who she claimed had committed 42 offences in three years, is involved in gangs and habitually carries a knife, but has never been jailed.